Three-dimensional data encoding method, three-dimensional data decoding method, three-dimensional data encoding device, and three-dimensional data decoding device

ABSTRACT

A three-dimensional data encoding method includes: encoding divided data items to generate encoded data items each corresponding to a respective one of the divided data items, the divided data items being included in subspaces obtained by dividing a current space including three-dimensional points, the divided data items each including one or more three-dimensional points among the three-dimensional points; and generating a bitstream including the encoded data items and control information items each corresponding to a respective one of the encoded data items. Each of the control information items includes a first identifier and a second identifier. The first identifier indicates a subspace corresponding to an encoded data item corresponding to the control information item, and the second identifier indicates a divided data item corresponding to the encoded data item corresponding to the control information item.

BACKGROUND 1. Technical Field

The present disclosure relates to a three-dimensional data encodingmethod, a three-dimensional data decoding method, a three-dimensionaldata encoding device, and a three-dimensional data decoding device.

2. Description of the Related Art

Devices or services utilizing three-dimensional data are expected tofind their widespread use in a wide range of fields, such as computervision that enables autonomous operations of cars or robots, mapinformation, monitoring, infrastructure inspection, and videodistribution. Three-dimensional data is obtained through various meansincluding a distance sensor such as a rangefinder, as well as a stereocamera and a combination of a plurality of monocular cameras.

Methods of representing three-dimensional data include a method known asa point cloud scheme that represents the shape of a three-dimensionalstructure by a point cloud in a three-dimensional space. In the pointcloud scheme, the positions and colors of a point cloud are stored.While point cloud is expected to be a mainstream method of representingthree-dimensional data, a massive amount of data of a point cloudnecessitates compression of the amount of three-dimensional data byencoding for accumulation and transmission, as in the case of atwo-dimensional moving picture (examples include Moving Picture ExpertsGroup-4 Advanced Video Coding (MPEG-4 AVC) and High Efficiency VideoCoding (HEVC) standardized by MPEG).

Meanwhile, point cloud compression is partially supported by, forexample, an open-source library (Point Cloud Library) for pointcloud-related processing.

Furthermore, a technique for searching for and displaying a facilitylocated in the surroundings of the vehicle by using three-dimensionalmap data is known (for example, see International Publication WO2014/020663).

SUMMARY

There has been a demand for reducing the processing amount of athree-dimensional data decoding device in encoding and decodingthree-dimensional data.

The present disclosure has an object to provide a three-dimensional dataencoding method, a three-dimensional data decoding method, athree-dimensional data encoding device, or a three-dimensional datadecoding device that is capable of reducing the processing amount of thethree-dimensional data decoding device.

In accordance with an aspect of the present disclosure, athree-dimensional data encoding method includes: encoding a plurality ofdivided data items to generate a plurality of encoded data items eachcorresponding to a respective one of the plurality of divided dataitems, the plurality of divided data items being included in a pluralityof subspaces obtained by dividing a current space including a pluralityof three-dimensional points, the plurality of divided data items eachincluding one or more three-dimensional points among the plurality ofthree-dimensional points; and generating a bitstream, the bitstreamincluding the plurality of encoded data items and a plurality of controlinformation items each corresponding to a respective one of theplurality of encoded data items, wherein each of the plurality ofcontrol information items includes a first identifier and a secondidentifier, the first identifier indicating a subspace corresponding toan encoded data item corresponding to the control information item amongthe plurality of subspaces, the second identifier indicating a divideddata item corresponding to the encoded data item corresponding to thecontrol information item among the plurality of divided data items.

In accordance with another aspect of the present disclosure, athree-dimensional data decoding method includes: obtaining firstidentifiers and second identifiers from a bitstream, the bitstreamincluding a plurality of encoded data items and a plurality of controlinformation items each corresponding to a respective one of theplurality of encoded data items, the first identifiers and the secondidentifiers being included in the plurality of control informationitems, the plurality of encoded data items being generated by encoding aplurality of divided data items, the plurality of divided data itemsbeing included in a plurality of subspaces obtained by dividing acurrent space including a plurality of three-dimensional points, theplurality of divided data items each including one or morethree-dimensional points among the plurality of three-dimensionalpoints, the first identifiers each indicating a subspace correspondingto an encoded data item corresponding to a corresponding one of theplurality of control information items among the plurality of subspaces,and the second identifiers each indicating a divided data itemcorresponding to an encoded data item corresponding to a correspondingone of the plurality of control information items among the plurality ofdivided data items; decoding the plurality of encoded data items toreconstruct the plurality of divided data items; and combining theplurality of divided data items together with reference to the firstidentifiers and the second identifiers to reconstruct the current space.

The present disclosure provides a three-dimensional data encodingmethod, a three-dimensional data decoding method, a three-dimensionaldata encoding device, or a three-dimensional data decoding device thatis capable of reducing the processing amount of the three-dimensionaldata decoding device.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the disclosure willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present disclosure.

FIG. 1 is a diagram illustrating a configuration of a three-dimensionaldata encoding and decoding system according to Embodiment 1;

FIG. 2 is a diagram illustrating a structure example of point cloud dataaccording to Embodiment 1;

FIG. 3 is a diagram illustrating a structure example of a data fileindicating the point cloud data according to Embodiment 1;

FIG. 4 is a diagram illustrating types of the point cloud data accordingto Embodiment 1;

FIG. 5 is a diagram illustrating a structure of a first encoderaccording to Embodiment 1;

FIG. 6 is a block diagram illustrating the first encoder according toEmbodiment 1;

FIG. 7 is a diagram illustrating a structure of a first decoderaccording to Embodiment 1;

FIG. 8 is a block diagram illustrating the first decoder according toEmbodiment 1;

FIG. 9 is a diagram illustrating a structure of a second encoderaccording to Embodiment 1;

FIG. 10 is a block diagram illustrating the second encoder according toEmbodiment 1;

FIG. 11 is a diagram illustrating a structure of a second decoderaccording to Embodiment 1;

FIG. 12 is a block diagram illustrating the second decoder according toEmbodiment 1;

FIG. 13 is a diagram illustrating a protocol stack related to PCCencoded data according to Embodiment 1;

FIG. 14 is a block diagram of an encoder according to Embodiment 1;

FIG. 15 is a block diagram of a decoder according to Embodiment 1;

FIG. 16 is a flowchart of encoding processing according to Embodiment 1;

FIG. 17 is a flowchart of decoding processing according to Embodiment 1;

FIG. 18 is a diagram illustrating a basic structure of ISOBMFF accordingto Embodiment 2;

FIG. 19 is a diagram illustrating a protocol stack according toEmbodiment 2;

FIG. 20 is a diagram illustrating an example where a NAL unit is storedin a file for codec 1 according to Embodiment 2;

FIG. 21 is a diagram illustrating an example where a NAL unit is storedin a file for codec 2 according to Embodiment 2;

FIG. 22 is a diagram illustrating a structure of a first multiplexeraccording to Embodiment 2;

FIG. 23 is a diagram illustrating a structure of a first demultiplexeraccording to Embodiment 2;

FIG. 24 is a diagram illustrating a structure of a second multiplexeraccording to Embodiment 2;

FIG. 25 is a diagram illustrating a structure of a second demultiplexeraccording to Embodiment 2;

FIG. 26 is a flowchart of processing performed by the first multiplexeraccording to Embodiment 2;

FIG. 27 is a flowchart of processing performed by the second multiplexeraccording to Embodiment 2;

FIG. 28 is a flowchart of processing performed by the firstdemultiplexer and the first decoder according to Embodiment 2;

FIG. 29 is a flowchart of processing performed by the seconddemultiplexer and the second decoder according to Embodiment 2;

FIG. 30 is a diagram illustrating structures of an encoder and a thirdmultiplexer according to Embodiment 3;

FIG. 31 is a diagram illustrating structures of a third demultiplexerand a decoder according to Embodiment 3;

FIG. 32 is a flowchart of processing performed by the third multiplexeraccording to Embodiment 3;

FIG. 33 is a flowchart of processing performed by the thirddemultiplexer and the decoder according to Embodiment 3;

FIG. 34 is a flowchart of processing performed by a three-dimensionaldata storage device according to Embodiment 3;

FIG. 35 is a flowchart of processing performed by a three-dimensionaldata acquisition device according to Embodiment 3;

FIG. 36 is a diagram illustrating structures of an encoder and amultiplexer according to Embodiment 4;

FIG. 37 is a diagram illustrating a structure example of encoded dataaccording to Embodiment 4;

FIG. 38 is a diagram illustrating a structure example of encoded dataand a NAL unit according to Embodiment 4;

FIG. 39 is a diagram illustrating a semantics example ofpcc_nal_unit_type according to Embodiment 4;

FIG. 40 is a diagram illustrating an example of a transmitting order ofNAL units according to Embodiment 4;

FIG. 41 is a flowchart of processing performed by a three-dimensionaldata encoding device according to Embodiment 4;

FIG. 42 is a flowchart of processing performed by a three-dimensionaldata decoding device according to Embodiment 4;

FIG. 43 is a flowchart of multiplexing processing according toEmbodiment 4;

FIG. 44 is a flowchart of demultiplexing processing according toEmbodiment 4;

FIG. 45 is a flowchart of processing performed by a three-dimensionaldata encoding device according to Embodiment 4;

FIG. 46 is a flowchart of processing performed by a three-dimensionaldata decoding device according to Embodiment 4;

FIG. 47 is a block diagram of a first encoder according to Embodiment 5;

FIG. 48 is a block diagram of a first decoder according to Embodiment 5;

FIG. 49 is a block diagram of a divider according to Embodiment 5;

FIG. 50 is a diagram illustrating an example of dividing slices andtiles according to Embodiment 5;

FIG. 51 is a diagram illustrating dividing pattern examples of slicesand tiles according to Embodiment 5;

FIG. 52 is a diagram illustrating an example of dependency according toEmbodiment 5;

FIG. 53 is a diagram illustrating a data decoding order according toEmbodiment 5;

FIG. 54 is a flowchart of encoding processing according to Embodiment 5;

FIG. 55 is a block diagram of a combiner according to Embodiment 5;

FIG. 56 is a diagram illustrating a structure example of encoded dataand a NAL unit according to Embodiment 5;

FIG. 57 is a flowchart of encoding processing according to Embodiment 5;

FIG. 58 is a flowchart of decoding processing according to Embodiment 5;

FIG. 59 is a flowchart of encoding processing according to Embodiment 5;and

FIG. 60 is a flowchart of decoding processing according to Embodiment 5.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In accordance with an aspect of the present disclosure, athree-dimensional data encoding method includes: encoding a plurality ofdivided data items to generate a plurality of encoded data items eachcorresponding to a respective one of the plurality of divided dataitems, the plurality of divided data items being included in a pluralityof subspaces obtained by dividing a current space including a pluralityof three-dimensional points, the plurality of divided data items eachincluding one or more three-dimensional points among the plurality ofthree-dimensional points; and generating a bitstream, the bitstreamincluding the plurality of encoded data items and a plurality of controlinformation items each corresponding to a respective one of theplurality of encoded data items, wherein each of the plurality ofcontrol information items includes a first identifier and a secondidentifier, the first identifier indicating a subspace corresponding toan encoded data item corresponding to the control information item amongthe plurality of subspaces, the second identifier indicating a divideddata item corresponding to the encoded data item corresponding to thecontrol information item among the plurality of divided data items.

Accordingly, a three-dimensional data decoding device that decodes thebitstream generated by the three-dimensional data encoding method caneasily reconstruct the current space by combining the divided data itemstogether with reference to the first identifier and the secondidentifier. Therefore, the three-dimensional data decoding device canreduce the processing amount.

For example, it is possible that the encoding includes encoding geometryinformation and attribute information of each of the one or morethree-dimensional points included in each of the plurality of divideddata items to generate encoded geometry information and encodedattribute information, each of the plurality of encoded data itemsincludes the encoded geometry information and the encoded attributeinformation, that each of the plurality of control information itemsincludes a geometry-information control information item for the encodedgeometry information and an attribute-information control informationitem for the encoded attribute information, and that the firstidentifier and the second identifier are included in thegeometry-information control information item for the encoded geometryinformation.

For example, it is also possible that in the bitstream, each of theplurality of control information items is located ahead of acorresponding one of the plurality of encoded data items.

In accordance with another aspect of the present disclosure, athree-dimensional data decoding method includes: obtaining firstidentifiers and second identifiers from a bitstream, the bitstreamincluding a plurality of encoded data items and a plurality of controlinformation items each corresponding to a respective one of theplurality of encoded data items, the first identifiers and the secondidentifiers being included in the plurality of control informationitems, the plurality of encoded data items being generated by encoding aplurality of divided data items, the plurality of divided data itemsbeing included in a plurality of subspaces obtained by dividing acurrent space including a plurality of three-dimensional points, theplurality of divided data items each including one or morethree-dimensional points among the plurality of three-dimensionalpoints, the first identifiers each indicating a subspace correspondingto an encoded data item corresponding to a corresponding one of theplurality of control information items among the plurality of subspaces,and the second identifiers each indicating a divided data itemcorresponding to an encoded data item corresponding to a correspondingone of the plurality of control information items among the plurality ofdivided data items; decoding the plurality of encoded data items toreconstruct the plurality of divided data items; and combining theplurality of divided data items together with reference to the firstidentifiers and the second identifiers to reconstruct the current space.

Accordingly, the three-dimensional data decoding method can easilyreconstruct the current space by combining the divided data itemstogether by using the first identifier and the second identifier.Therefore, the method can reduce the processing amount of athree-dimensional data decoding device.

For example, it is possible that each of the plurality of encoded dataitems is generated by encoding geometry information and attributeinformation of each of the one or more three-dimensional points includedin a divided data item corresponding to the each of the encoded dataitems among the plurality of divided data items to generate encodedgeometry information and encoded attribute information, that the each ofthe plurality of encoded data items includes the encoded geometryinformation and the encoded attribute information, that each of theplurality of control information items includes a geometry-informationcontrol information item for the encoded geometry information and anattribute-information control information item for the encoded attributeinformation, and that each of the first identifiers and each of thesecond identifiers are included in the geometry-information controlinformation item corresponding to the corresponding one of the pluralityof the control information items.

For example, it is also possible that in the bitstream, each of theplurality of control information items is located ahead of acorresponding one of the plurality of encoded data items.

In accordance with still another aspect of the present disclosure, athree-dimensional data encoding device includes: a processor; andmemory, wherein, using the memory, the processor: encodes a plurality ofdivided data items to generate a plurality of encoded data items eachcorresponding to a respective one of the plurality of divided dataitems, the plurality of divided data items being included in a pluralityof subspaces obtained by dividing a current space including a pluralityof three-dimensional points, the plurality of divided data items eachincluding one or more three-dimensional points among the plurality ofthree-dimensional points; and generates a bitstream, the bitstreamincluding the plurality of encoded data items and a plurality of controlinformation items each corresponding to a respective one of theplurality of encoded data items, wherein each of the plurality ofcontrol information items includes a first identifier and a secondidentifier, the first identifier indicating a subspace corresponding toan encoded data item corresponding to the control information item amongthe plurality of subspaces, the second identifier indicating a divideddata item corresponding to the encoded data item corresponding to thecontrol information item among the plurality of divided data items.

Accordingly, the three-dimensional data decoding device that decodes thebitstream generated by the three-dimensional data encoding device caneasily reconstruct the current space by combining the divided data itemstogether by using the first identifier and the second identifier.Therefore, it is possible to reduce the processing amount of thethree-dimensional data decoding device.

In accordance with still another aspect of the present disclosure, athree-dimensional data decoding device includes: a processor; andmemory, wherein, using the memory, the processor: obtains firstidentifiers and second identifiers from a bitstream, the bitstreamincluding a plurality of encoded data items and a plurality of controlinformation items each corresponding to a respective one of theplurality of encoded data items, the first identifiers and the secondidentifiers being included in the plurality of control informationitems, the plurality of encoded data items being generated by encoding aplurality of divided data items, the plurality of divided data itemsbeing included in a plurality of subspaces obtained by dividing acurrent space including a plurality of three-dimensional points, theplurality of divided data items each including one or morethree-dimensional points among the plurality of three-dimensionalpoints, the first identifiers each indicating a subspace correspondingto an encoded data item corresponding to a corresponding one of theplurality of control information items among the plurality of subspaces,and the second identifiers each indicating a divided data itemcorresponding to an encoded data item corresponding to a correspondingone of the plurality of control information items among the plurality ofdivided data items; decodes the plurality of encoded data items toreconstruct the plurality of divided data items; and combines theplurality of divided data items together with reference to the firstidentifiers and the second identifiers to reconstruct the current space.

Accordingly, the three-dimensional data decoding device can easilyreconstruct the current space by combining the divided data itemstogether by using the first identifier and the second identifier.Therefore, the three-dimensional data decoding device can reduce theprocessing amount.

Note that these general or specific aspects may be implemented as asystem, a method, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or may beimplemented as any combination of a system, a method, an integratedcircuit, a computer program, and a recording medium.

The following describes embodiments with reference to the drawings. Notethat the following embodiments show exemplary embodiments of the presentdisclosure. The numerical values, shapes, materials, structuralcomponents, the arrangement and connection of the structural components,steps, the processing order of the steps, etc. shown in the followingembodiments are mere examples, and thus are not intended to limit thepresent disclosure. Of the structural components described in thefollowing embodiments, structural components not recited in any one ofthe independent claims that indicate the broadest concepts will bedescribed as optional structural components.

Embodiment 1

When using encoded data of a point cloud in a device or for a service inpractice, required information for the application is desirablytransmitted and received in order to reduce the network bandwidth.However, conventional encoding structures for three-dimensional datahave no such a function, and there is also no encoding method for such afunction.

Embodiment 1 described below relates to a three-dimensional dataencoding method and a three-dimensional data encoding device for encodeddata of a three-dimensional point cloud that provides a function oftransmitting and receiving required information for an application, athree-dimensional data decoding method and a three-dimensional datadecoding device for decoding the encoded data, a three-dimensional datamultiplexing method for multiplexing the encoded data, and athree-dimensional data transmission method for transmitting the encodeddata.

In particular, at present, a first encoding method and a second encodingmethod are under investigation as encoding methods (encoding schemes)for point cloud data. However, there is no method defined for storingthe configuration of encoded data and the encoded data in a systemformat. Thus, there is a problem that an encoder cannot perform an MUXprocess (multiplexing), transmission, or accumulation of data.

In addition, there is no method for supporting a format that involvestwo codecs, the first encoding method and the second encoding method,such as point cloud compression (PCC).

With regard to this embodiment, a configuration of PCC-encoded data thatinvolves two codecs, a first encoding method and a second encodingmethod, and a method of storing the encoded data in a system format willbe described.

A configuration of a three-dimensional data (point cloud data) encodingand decoding system according to this embodiment will be firstdescribed. FIG. 1 is a diagram showing an example of a configuration ofthe three-dimensional data encoding and decoding system according tothis embodiment. As shown in FIG. 1 , the three-dimensional dataencoding and decoding system includes three-dimensional data encodingsystem 4601, three-dimensional data decoding system 4602, sensorterminal 4603, and external connector 4604.

Three-dimensional data encoding system 4601 generates encoded data ormultiplexed data by encoding point cloud data, which isthree-dimensional data. Three-dimensional data encoding system 4601 maybe a three-dimensional data encoding device implemented by a singledevice or a system implemented by a plurality of devices. Thethree-dimensional data encoding device may include a part of a pluralityof processors included in three-dimensional data encoding system 4601.

Three-dimensional data encoding system 4601 includes point cloud datageneration system 4611, presenter 4612, encoder 4613, multiplexer 4614,input/output unit 4615, and controller 4616. Point cloud data generationsystem 4611 includes sensor information obtainer 4617, and point clouddata generator 4618.

Sensor information obtainer 4617 obtains sensor information from sensorterminal 4603, and outputs the sensor information to point cloud datagenerator 4618. Point cloud data generator 4618 generates point clouddata from the sensor information, and outputs the point cloud data toencoder 4613.

Presenter 4612 presents the sensor information or point cloud data to auser. For example, presenter 4612 displays information or an image basedon the sensor information or point cloud data.

Encoder 4613 encodes (compresses) the point cloud data, and outputs theresulting encoded data, control information (signaling information)obtained in the course of the encoding, and other additional informationto multiplexer 4614. The additional information includes the sensorinformation, for example.

Multiplexer 4614 generates multiplexed data by multiplexing the encodeddata, the control information, and the additional information inputthereto from encoder 4613. A format of the multiplexed data is a fileformat for accumulation or a packet format for transmission, forexample.

Input/output unit 4615 (a communication unit or interface, for example)outputs the multiplexed data to the outside. Alternatively, themultiplexed data may be accumulated in an accumulator, such as aninternal memory. Controller 4616 (or an application executor) controlseach processor. That is, controller 4616 controls the encoding, themultiplexing, or other processing.

Note that the sensor information may be input to encoder 4613 ormultiplexer 4614. Alternatively, input/output unit 4615 may output thepoint cloud data or encoded data to the outside as it is.

A transmission signal (multiplexed data) output from three-dimensionaldata encoding system 4601 is input to three-dimensional data decodingsystem 4602 via external connector 4604.

Three-dimensional data decoding system 4602 generates point cloud data,which is three-dimensional data, by decoding the encoded data ormultiplexed data. Note that three-dimensional data decoding system 4602may be a three-dimensional data decoding device implemented by a singledevice or a system implemented by a plurality of devices. Thethree-dimensional data decoding device may include a part of a pluralityof processors included in three-dimensional data decoding system 4602.

Three-dimensional data decoding system 4602 includes sensor informationobtainer 4621, input/output unit 4622, demultiplexer 4623, decoder 4624,presenter 4625, user interface 4626, and controller 4627.

Sensor information obtainer 4621 obtains sensor information from sensorterminal 4603.

Input/output unit 4622 obtains the transmission signal, decodes thetransmission signal into the multiplexed data (file format or packet),and outputs the multiplexed data to demultiplexer 4623.

Demultiplexer 4623 obtains the encoded data, the control information,and the additional information from the multiplexed data, and outputsthe encoded data, the control information, and the additionalinformation to decoder 4624.

Decoder 4624 reconstructs the point cloud data by decoding the encodeddata.

Presenter 4625 presents the point cloud data to a user. For example,presenter 4625 displays information or an image based on the point clouddata. User interface 4626 obtains an indication based on a manipulationby the user. Controller 4627 (or an application executor) controls eachprocessor. That is, controller 4627 controls the demultiplexing, thedecoding, the presentation, or other processing.

Note that input/output unit 4622 may obtain the point cloud data orencoded data as it is from the outside. Presenter 4625 may obtainadditional information, such as sensor information, and presentinformation based on the additional information. Presenter 4625 mayperform a presentation based on an indication from a user obtained onuser interface 4626.

Sensor terminal 4603 generates sensor information, which is informationobtained by a sensor. Sensor terminal 4603 is a terminal provided with asensor or a camera. For example, sensor terminal 4603 is a mobile body,such as an automobile, a flying object, such as an aircraft, a mobileterminal, or a camera.

Sensor information that can be generated by sensor terminal 4603includes (1) the distance between sensor terminal 4603 and an object orthe reflectance of the object obtained by LIDAR, a millimeter waveradar, or an infrared sensor or (2) the distance between a camera and anobject or the reflectance of the object obtained by a plurality ofmonocular camera images or a stereo-camera image, for example. Thesensor information may include the posture, orientation, gyro (angularvelocity), position (GPS information or altitude), velocity, oracceleration of the sensor, for example. The sensor information mayinclude air temperature, air pressure, air humidity, or magnetism, forexample.

External connector 4604 is implemented by an integrated circuit (LSI orIC), an external accumulator, communication with a cloud server via theInternet, or broadcasting, for example.

Next, point cloud data will be described. FIG. 2 is a diagram showing aconfiguration of point cloud data. FIG. 3 is a diagram showing aconfiguration example of a data file describing information of the pointcloud data.

Point cloud data includes data on a plurality of points. Data on eachpoint includes geometry information (three-dimensional coordinates) andattribute information associated with the geometry information. A set ofa plurality of such points is referred to as a point cloud. For example,a point cloud indicates a three-dimensional shape of an object.

Geometry information (position), such as three-dimensional coordinates,may be referred to as geometry. Data on each point may include attributeinformation (attribute) on a plurality of types of attributes. A type ofattribute is color or reflectance, for example.

One piece of attribute information may be associated with one piece ofgeometry information, or attribute information on a plurality ofdifferent types of attributes may be associated with one piece ofgeometry information. Alternatively, a plurality of pieces of attributeinformation on the same type of attribute may be associated with onepiece of geometry information.

The configuration example of a data file shown in FIG. 3 is an examplein which geometry information and attribute information are associatedwith each other in a one-to-one relationship, and geometry informationand attribute information on N points forming point cloud data areshown.

The geometry information is information on three axes, specifically, anx-axis, a y-axis, and a z-axis, for example. The attribute informationis RGB color information, for example. A representative data file is plyfile, for example.

Next, types of point cloud data will be described. FIG. 4 is a diagramshowing types of point cloud data. As shown in FIG. 4 , point cloud dataincludes a static object and a dynamic object.

The static object is three-dimensional point cloud data at an arbitrarytime (a time point). The dynamic object is three-dimensional point clouddata that varies with time. In the following, three-dimensional pointcloud data associated with a time point will be referred to as a PCCframe or a frame.

The object may be a point cloud whose range is limited to some extent,such as ordinary video data, or may be a large point cloud whose rangeis not limited, such as map information.

There are point cloud data having varying densities. There may be sparsepoint cloud data and dense point cloud data.

In the following, each processor will be described in detail. Sensorinformation is obtained by various means, including a distance sensorsuch as LIDAR or a range finder, a stereo camera, or a combination of aplurality of monocular cameras. Point cloud data generator 4618generates point cloud data based on the sensor information obtained bysensor information obtainer 4617. Point cloud data generator 4618generates geometry information as point cloud data, and adds attributeinformation associated with the geometry information to the geometryinformation.

When generating geometry information or adding attribute information,point cloud data generator 4618 may process the point cloud data. Forexample, point cloud data generator 4618 may reduce the data amount byomitting a point cloud whose position coincides with the position ofanother point cloud. Point cloud data generator 4618 may also convertthe geometry information (such as shifting, rotating or normalizing theposition) or render the attribute information.

Note that, although FIG. 1 shows point cloud data generation system 4611as being included in three-dimensional data encoding system 4601, pointcloud data generation system 4611 may be independently provided outsidethree-dimensional data encoding system 4601.

Encoder 4613 generates encoded data by encoding point cloud dataaccording to an encoding method previously defined. In general, thereare the two types of encoding methods described below. One is anencoding method using geometry information, which will be referred to asa first encoding method, hereinafter. The other is an encoding methodusing a video codec, which will be referred to as a second encodingmethod, hereinafter.

Decoder 4624 decodes the encoded data into the point cloud data usingthe encoding method previously defined.

Multiplexer 4614 generates multiplexed data by multiplexing the encodeddata in an existing multiplexing method. The generated multiplexed datais transmitted or accumulated. Multiplexer 4614 multiplexes not only thePCC-encoded data but also another medium, such as a video, an audio,subtitles, an application, or a file, or reference time information.Multiplexer 4614 may further multiplex attribute information associatedwith sensor information or point cloud data.

Multiplexing schemes or file formats include ISOBMFF, MPEG-DASH, whichis a transmission scheme based on ISOBMFF, MMT, MPEG-2 TS Systems, orRMP, for example.

Demultiplexer 4623 extracts PCC-encoded data, other media, timeinformation and the like from the multiplexed data.

Input/output unit 4615 transmits the multiplexed data in a methodsuitable for the transmission medium or accumulation medium, such asbroadcasting or communication. Input/output unit 4615 may communicatewith another device over the Internet or communicate with anaccumulator, such as a cloud server.

As a communication protocol, http, ftp, TCP, UDP or the like is used.The pull communication scheme or the push communication scheme can beused.

A wired transmission or a wireless transmission can be used. For thewired transmission, Ethernet (registered trademark), USB, RS-232C, HDMI(registered trademark), or a coaxial cable is used, for example. For thewireless transmission, wireless LAN, Wi-Fi (registered trademark),Bluetooth (registered trademark), or a millimeter wave is used, forexample.

As a broadcasting scheme, DVB-T2, DVB-S2, DVB-C2, ATSC3.0, or ISDB-S3 isused, for example.

FIG. 5 is a diagram showing a configuration of first encoder 4630, whichis an example of encoder 4613 that performs encoding in the firstencoding method. FIG. 6 is a block diagram showing first encoder 4630.First encoder 4630 generates encoded data (encoded stream) by encodingpoint cloud data in the first encoding method. First encoder 4630includes geometry information encoder 4631, attribute informationencoder 4632, additional information encoder 4633, and multiplexer 4634.

First encoder 4630 is characterized by performing encoding by keeping athree-dimensional structure in mind. First encoder 4630 is furthercharacterized in that attribute information encoder 4632 performsencoding using information obtained from geometry information encoder4631. The first encoding method is referred to also as geometry-basedPCC (GPCC).

Point cloud data is PCC point cloud data like a PLY file or PCC pointcloud data generated from sensor information, and includes geometryinformation (position), attribute information (attribute), and otheradditional information (metadata). The geometry information is input togeometry information encoder 4631, the attribute information is input toattribute information encoder 4632, and the additional information isinput to additional information encoder 4633.

Geometry information encoder 4631 generates encoded geometry information(compressed geometry), which is encoded data, by encoding geometryinformation. For example, geometry information encoder 4631 encodesgeometry information using an N-ary tree structure, such as an octree.Specifically, in the case of an octree, a current space is divided intoeight nodes (subspaces), 8-bit information (occupancy code) thatindicates whether each node includes a point cloud or not is generated.A node including a point cloud is further divided into eight nodes, and8-bit information that indicates whether each of the eight nodesincludes a point cloud or not is generated. This process is repeateduntil a predetermined level is reached or the number of the point cloudsincluded in each node becomes equal to or less than a threshold.

Attribute information encoder 4632 generates encoded attributeinformation (compressed attribute), which is encoded data, by encodingattribute information using configuration information generated bygeometry information encoder 4631. For example, attribute informationencoder 4632 determines a reference point (reference node) that is to bereferred to in encoding a current point (current node) to be processedbased on the octree structure generated by geometry information encoder4631. For example, attribute information encoder 4632 refers to a nodewhose parent node in the octree is the same as the parent node of thecurrent node, of peripheral nodes or neighboring nodes. Note that themethod of determining a reference relationship is not limited to thismethod.

The process of encoding attribute information may include at least oneof a quantization process, a prediction process, and an arithmeticencoding process. In this case, “refer to” means using a reference nodefor calculating a predicted value of attribute information or using astate of a reference node (occupancy information that indicates whethera reference node includes a point cloud or not, for example) fordetermining a parameter of encoding. For example, the parameter ofencoding is a quantization parameter in the quantization process or acontext or the like in the arithmetic encoding.

Additional information encoder 4633 generates encoded additionalinformation (compressed metadata), which is encoded data, by encodingcompressible data of additional information.

Multiplexer 4634 generates encoded stream (compressed stream), which isencoded data, by multiplexing encoded geometry information, encodedattribute information, encoded additional information, and otheradditional information. The generated encoded stream is output to aprocessor in a system layer (not shown).

Next, first decoder 4640, which is an example of decoder 4624 thatperforms decoding in the first encoding method, will be described. FIG.7 is a diagram showing a configuration of first decoder 4640. FIG. 8 isa block diagram showing first decoder 4640. First decoder 4640 generatespoint cloud data by decoding encoded data (encoded stream) encoded inthe first encoding method in the first encoding method. First decoder4640 includes demultiplexer 4641, geometry information decoder 4642,attribute information decoder 4643, and additional information decoder4644.

An encoded stream (compressed stream), which is encoded data, is inputto first decoder 4640 from a processor in a system layer (not shown).

Demultiplexer 4641 separates encoded geometry information (compressedgeometry), encoded attribute information (compressed attribute), encodedadditional information (compressed metadata), and other additionalinformation from the encoded data.

Geometry information decoder 4642 generates geometry information bydecoding the encoded geometry information. For example, geometryinformation decoder 4642 restores the geometry information on a pointcloud represented by three-dimensional coordinates from encoded geometryinformation represented by an N-ary structure, such as an octree.

Attribute information decoder 4643 decodes the encoded attributeinformation based on configuration information generated by geometryinformation decoder 4642. For example, attribute information decoder4643 determines a reference point (reference node) that is to bereferred to in decoding a current point (current node) to be processedbased on the octree structure generated by geometry information decoder4642. For example, attribute information decoder 4643 refers to a nodewhose parent node in the octree is the same as the parent node of thecurrent node, of peripheral nodes or neighboring nodes. Note that themethod of determining a reference relationship is not limited to thismethod.

The process of decoding attribute information may include at least oneof an inverse quantization process, a prediction process, and anarithmetic decoding process. In this case, “refer to” means using areference node for calculating a predicted value of attributeinformation or using a state of a reference node (occupancy informationthat indicates whether a reference node includes a point cloud or not,for example) for determining a parameter of decoding. For example, theparameter of decoding is a quantization parameter in the inversequantization process or a context or the like in the arithmeticdecoding.

Additional information decoder 4644 generates additional information bydecoding the encoded additional information. First decoder 4640 usesadditional information required for the decoding process for thegeometry information and the attribute information in the decoding, andoutputs additional information required for an application to theoutside.

Next, second encoder 4650, which is an example of encoder 4613 thatperforms encoding in the second encoding method, will be described. FIG.9 is a diagram showing a configuration of second encoder 4650. FIG. 10is a block diagram showing second encoder 4650.

Second encoder 4650 generates encoded data (encoded stream) by encodingpoint cloud data in the second encoding method. Second encoder 4650includes additional information generator 4651, geometry image generator4652, attribute image generator 4653, video encoder 4654, additionalinformation encoder 4655, and multiplexer 4656.

Second encoder 4650 is characterized by generating a geometry image andan attribute image by projecting a three-dimensional structure onto atwo-dimensional image, and encoding the generated geometry image andattribute image in an existing video encoding scheme. The secondencoding method is referred to as video-based PCC (VPCC).

Point cloud data is PCC point cloud data like a PLY file or PCC pointcloud data generated from sensor information, and includes geometryinformation (position), attribute information (attribute), and otheradditional information (metadata).

Additional information generator 4651 generates map information on aplurality of two-dimensional images by projecting a three-dimensionalstructure onto a two-dimensional image.

Geometry image generator 4652 generates a geometry image based on thegeometry information and the map information generated by additionalinformation generator 4651. The geometry image is a distance image inwhich distance (depth) is indicated as a pixel value, for example. Thedistance image may be an image of a plurality of point clouds viewedfrom one point of view (an image of a plurality of point cloudsprojected onto one two-dimensional plane), a plurality of images of aplurality of point clouds viewed from a plurality of points of view, ora single image integrating the plurality of images.

Attribute image generator 4653 generates an attribute image based on theattribute information and the map information generated by additionalinformation generator 4651. The attribute image is an image in whichattribute information (color (RGB), for example) is indicated as a pixelvalue, for example. The image may be an image of a plurality of pointclouds viewed from one point of view (an image of a plurality of pointclouds projected onto one two-dimensional plane), a plurality of imagesof a plurality of point clouds viewed from a plurality of points ofview, or a single image integrating the plurality of images.

Video encoder 4654 generates an encoded geometry image (compressedgeometry image) and an encoded attribute image (compressed attributeimage), which are encoded data, by encoding the geometry image and theattribute image in a video encoding scheme. Note that, as the videoencoding scheme, any well-known encoding method can be used. Forexample, the video encoding scheme is AVC or HEVC.

Additional information encoder 4655 generates encoded additionalinformation (compressed metadata) by encoding the additionalinformation, the map information and the like included in the pointcloud data.

Multiplexer 4656 generates an encoded stream (compressed stream), whichis encoded data, by multiplexing the encoded geometry image, the encodedattribute image, the encoded additional information, and otheradditional information. The generated encoded stream is output to aprocessor in a system layer (not shown).

Next, second decoder 4660, which is an example of decoder 4624 thatperforms decoding in the second encoding method, will be described. FIG.11 is a diagram showing a configuration of second decoder 4660. FIG. 12is a block diagram showing second decoder 4660. Second decoder 4660generates point cloud data by decoding encoded data (encoded stream)encoded in the second encoding method in the second encoding method.Second decoder 4660 includes demultiplexer 4661, video decoder 4662,additional information decoder 4663, geometry information generator4664, and attribute information generator 4665.

An encoded stream (compressed stream), which is encoded data, is inputto second decoder 4660 from a processor in a system layer (not shown).

Demultiplexer 4661 separates an encoded geometry image (compressedgeometry image), an encoded attribute image (compressed attributeimage), an encoded additional information (compressed metadata), andother additional information from the encoded data.

Video decoder 4662 generates a geometry image and an attribute image bydecoding the encoded geometry image and the encoded attribute image in avideo encoding scheme. Note that, as the video encoding scheme, anywell-known encoding method can be used. For example, the video encodingscheme is AVC or HEVC.

Additional information decoder 4663 generates additional informationincluding map information or the like by decoding the encoded additionalinformation.

Geometry information generator 4664 generates geometry information fromthe geometry image and the map information. Attribute informationgenerator 4665 generates attribute information from the attribute imageand the map information.

Second decoder 4660 uses additional information required for decoding inthe decoding, and outputs additional information required for anapplication to the outside.

In the following, a problem with the PCC encoding scheme will bedescribed. FIG. 13 is a diagram showing a protocol stack relating toPCC-encoded data. FIG. 13 shows an example in which PCC-encoded data ismultiplexed with other medium data, such as a video (HEVC, for example)or an audio, and transmitted or accumulated.

A multiplexing scheme and a file format have a function of multiplexingvarious encoded data and transmitting or accumulating the data. Totransmit or accumulate encoded data, the encoded data has to beconverted into a format for the multiplexing scheme. For example, withHEVC, a technique for storing encoded data in a data structure referredto as a NAL unit and storing the NAL unit in ISOBMFF is prescribed.

At present, a first encoding method (Codec1) and a second encodingmethod (Codec2) are under investigation as encoding methods for pointcloud data. However, there is no method defined for storing theconfiguration of encoded data and the encoded data in a system format.Thus, there is a problem that an encoder cannot perform an MUX process(multiplexing), transmission, or accumulation of data.

Note that, in the following, the term “encoding method” means any of thefirst encoding method and the second encoding method unless a particularencoding method is specified.

In the following, a way of defining a NAL unit according to thisembodiment will be described. For example, with a conventional codec,such as HEVC, a NAL unit in one format is defined for one codec.However, there has been no method that supports a format that involvestwo codecs, that is, the first encoding method and the second encodingmethod, such as PCC (such a codec will be referred to as a PCC codec,hereinafter).

First, encoder 4670 having the functions of both first encoder 4630 andsecond encoder 4650 described above and decoder 4680 having thefunctions of both first decoder 4640 and second decoder 4660 describedabove will be described.

FIG. 14 is a block diagram showing encoder 4670 according to thisembodiment. Encoder 4670 includes first encoder 4630 and second encoder4650 described above and multiplexer 4671. Multiplexer 4671 multiplexesencoded data generated by first encoder 4630 and encoded data generatedby second encoder 4650, and outputs the resulting encoded data.

FIG. 15 is a block diagram showing decoder 4680 according to thisembodiment. Decoder 4680 includes first decoder 4640 and second decoder4660 described above and demultiplexer 4681. Demultiplexer 4681 extractsencoded data generated using the first encoding method and encoded datagenerated using second encoding method from the input encoded data.Demultiplexer 4681 outputs the encoded data generated using the firstencoding method to first decoder 4640, and outputs the encoded datagenerated using the second encoding method to second decoder 4660.

With the configuration described above, encoder 4670 can encode pointcloud data by selectively using the first encoding method or the secondencoding method. Decoder 4680 can decode encoded data encoded using thefirst encoding method, encoded data using the second encoding method,and encoded data encoded using both the first encoding method and thesecond encoding method.

For example, encoder 4670 may change the encoding method (between thefirst encoding method and the second encoding method) on apoint-cloud-data basis or on a frame basis. Alternatively, encoder 4670may change the encoding method on the basis of an encodable unit.

For example, encoder 4670 generates encoded data (encoded stream)including the identification information for a PCC codec.

Demultiplexer 4681 in decoder 4680 identifies data using theidentification information for a PCC codec, for example. When the datais data encoded in the first encoding method, demultiplexer 4681 outputsthe data to first decoder 4640. When the data is data encoded in thesecond encoding method, demultiplexer 4681 outputs the data to seconddecoder 4660.

Encoder 4670 may transmit, as the control information, informationindicating whether both the encoding methods are used or any one of theencoding methods is used, in addition to the identification informationfor the PCC codec.

Next, an encoding process according to this embodiment will bedescribed. FIG. 16 is a flowchart showing an encoding process accordingto this embodiment. Using the identification information for a PCC codecallows an encoding process ready for a plurality of codecs.

First, encoder 4670 encodes PCC data in both or one of the codecs, thatis, the first encoding method and the second encoding method (S4681).

When the codec used is the second encoding method (if “second encodingmethod” in S4682), encoder 4670 sets pcc_codec_type in the NAL unitheader to a value that indicates that data included in the payload ofthe NAL unit is data encoded in the second encoding method (S4683).Encoder 4670 then sets pcc_nal_unit_type in the NAL unit header to theidentifier of the NAL unit for the second encoding method (S4684).Encoder 4670 then generates a NAL unit having the set NAL unit headerand including the encoded data in the payload. Encoder 4670 thentransmits the generated NAL unit (S4685).

On the other hand, when the codec used is the first encoding method (if“first encoding method” in S4682), encoder 4670 sets pcc_codec_type inthe NAL unit header to a value that indicates that data included in thepayload of the NAL unit is data encoded in the first encoding method(S4686). Encoder 4670 then sets pcc_nal_unit_type in the NAL unit headerto the identifier of the NAL unit for the first encoding method (S4687).Encoder 4670 then generates a NAL unit having the set NAL unit headerand including the encoded data in the payload. Encoder 4670 thentransmits the generated NAL unit (S4685).

Next, a decoding process according to this embodiment will be described.FIG. 17 is a flowchart showing a decoding process according to thisembodiment. Using the identification information for a PCC codec allowsa decoding process ready for a plurality of codecs.

First, decoder 4680 receives a NAL unit (S4691). For example, the NALunit is the NAL unit generated in the process by encoder 4670 describedabove.

Decoder 4680 then determines whether pcc_codec_type in the NAL unitheader indicates the first encoding method or the second encoding method(S4692).

When pcc_codec_type indicates the second encoding method (if “secondencoding method” in S4692), decoder 4680 determines that the dataincluded in the payload of the NAL unit is data encoded in the secondencoding method (S4693). Decoder 4680 then identifies the data based onthe determination that pcc_nal_unit_type in the NAL unit header is theidentifier of the NAL unit for the second encoding method (S4694).Decoder 4680 then decodes the PCC data in a decoding process for thesecond encoding method (S4695).

On the other hand, when pcc_codec_type indicates the first encodingmethod (if “first encoding method” in S4692), decoder 4680 determinesthat the data included in the payload of the NAL unit is data encoded inthe first encoding method (S4696). Decoder 4680 then identifies the databased on the determination that pcc_nal_unit_type in the NAL unit headeris the identifier of the NAL unit for the first encoding method (S4697).Decoder 4680 then decodes the PCC data in a decoding process for thefirst encoding method (S46980).

As described above, the three-dimensional data encoding device accordingto an aspect of the present disclosure generates an encoded stream byencoding three-dimensional data (point cloud data, for example), andstores information indicating the encoding method used for the encodingamong the first encoding method and the second encoding method(identification information for the codec, for example) in the controlinformation (a parameter set, for example) for the encoded stream.

With such a configuration, the three-dimensional data decoding devicecan determine the encoding method used for the encoding from theinformation stored in the control information, when decoding the encodedstream generated by the three-dimensional data encoding device.Therefore, the three-dimensional data decoding device can correctlydecode the encoded stream even when a plurality of encoding methods areused.

The three-dimensional data includes geometry information, for example.In the encoding described above, the three-dimensional data encodingdevice encodes the geometry information. In the storage described above,the three-dimensional data encoding device stores the informationindicating the encoding method used for the encoding of the geometryinformation among the first encoding method and the second encodingmethod in the control information for the geometry information.

The three-dimensional data includes geometry information and attributeinformation, for example. In the encoding described above, thethree-dimensional data encoding device encodes the geometry informationand the attribute information. In the storage described above, thethree-dimensional data encoding device stores the information indicatingthe encoding method used for the encoding of the geometry informationamong the first encoding method and the second encoding method in thecontrol information for the geometry information, and stores theinformation indicating the encoding method used for the encoding of theattribute information among the first encoding method and the secondencoding method in the control information for the attributeinformation.

With such a configuration, different encoding methods can be used forthe geometry information and the attribute information, and therefore,the coding efficiency can be improved.

For example, the three-dimensional data encoding method further includesstoring the encoded stream in one or more units (NAL units, forexample).

For example, the unit includes information (pcc_nal_unit_type, forexample) indicating the type of data included in the unit that has aformat that is common to the first encoding method and the secondencoding method and is independently defined for the first encodingmethod and the second encoding method.

For example, the unit includes information (codec1_nal_unit_type orcodec1_nal_unit_type, for example) indicating the type of data includedin the unit that has different formats for the first encoding method andthe second encoding method and is independently defined for the firstencoding method and the second encoding method.

For example, the unit includes information (pcc_nal_unit_type, forexample) indicating the type of data included in the unit that has aformat that is common to the first encoding method and the secondencoding method and is commonly defined for the first encoding methodand the second encoding method.

For example, the three-dimensional data encoding device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

The three-dimensional data decoding device according to this embodimentdetermines the encoding method used for encoding of an encoded streamobtained by encoding of three-dimensional data based on the informationindicating the encoding method used for the encoding of thethree-dimensional data among the first encoding method and the secondencoding method (identification information for the codec, for example)included in the control information (a parameter set, for example) forthe encoded stream, and decodes the encoded stream using the determinedencoding method.

With such a configuration, the three-dimensional data decoding devicecan determine the encoding method used for the encoding from theinformation stored in the control information, when decoding the encodedstream. Therefore, the three-dimensional data decoding device cancorrectly decode the encoded stream even when a plurality of encodingmethods are used.

The three-dimensional data includes geometry information, and theencoded stream includes encoded data of the geometry information, forexample. In the determination described above, the three-dimensionaldata decoding device determines the encoding method used for theencoding of the geometry information based on the information indicatingthe encoding method used for the encoding of the geometry informationamong the first encoding method and the second encoding method includedin the control information for the geometry information included in theencoded stream. In the decoding described above, the three-dimensionaldata decoding device decodes the encoded data of the geometryinformation using the determined encoding method used for the encodingof the geometry information.

The three-dimensional data includes geometry information and attributeinformation, and the encoded stream includes encoded data of thegeometry information and encoded data of the attribute information, forexample. In the determination described above, the three-dimensionaldata decoding device determines the encoding method used for theencoding of the geometry information based on the information indicatingthe encoding method used for the encoding of the geometry informationamong the first encoding method and the second encoding method includedin the control information for the geometry information included in theencoded stream, and determines the encoding method used for the encodingof the attribute information based on the information indicating theencoding method used for the encoding of the attribute information amongthe first encoding method and the second encoding method included in thecontrol information for the attribute information included in theencoded stream. In the decoding described above, the three-dimensionaldata decoding device decodes the encoded data of the geometryinformation using the determined encoding method used for the encodingof the geometry information, and decodes the encoded data of theattribute information using the determined encoding method used for theencoding of the attribute information.

With such a configuration, different encoding methods can be used forthe geometry information and the attribute information, and therefore,the coding efficiency can be improved.

For example, the encoded stream is stored in one or more units (NALunits, for example), and the three-dimensional data decoding devicefurther obtains the encoded stream from the one or more units.

For example, the unit includes information (pcc_nal_unit_type, forexample) indicating the type of data included in the unit that has aformat that is common to the first encoding method and the secondencoding method and is independently defined for the first encodingmethod and the second encoding method.

For example, the unit includes information (codec1_nal_unit_type orcodec1_nal_unit_type, for example) indicating the type of data includedin the unit that has different formats for the first encoding method andthe second encoding method and is independently defined for the firstencoding method and the second encoding method.

For example, the unit includes information (pcc_nal_unit_type, forexample) indicating the type of data included in the unit that has aformat that is common to the first encoding method and the secondencoding method and is commonly defined for the first encoding methodand the second encoding method.

For example, the three-dimensional data decoding device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

Embodiment 2

In Embodiment 2, a method of storing the NAL unit in an ISOBMFF filewill be described.

ISOBMFF is a file format standard prescribed in ISO/IEC14496-12. ISOBMFFis a standard that does not depend on any medium, and prescribes aformat that allows various media, such as a video, an audio, and a text,to be multiplexed and stored.

A basic structure (file) of ISOBMFF will be described. A basic unit ofISOBMFF is a box. A box is formed by type, length, and data, and a fileis a set of various types of boxes.

FIG. 18 is a diagram showing a basic structure (file) of ISOBMFF. A filein ISOBMFF includes boxes, such as ftyp that indicates the brand of thefile by four-character code (4CC), moov that stores metadata, such ascontrol information (signaling information), and mdat that stores data.

A method for storing each medium in the ISOBMFF file is separatelyprescribed. For example, a method of storing an AVC video or an HEVCvideo is prescribed in ISO/IEC14496-15. Here, it can be contemplated toexpand the functionality of ISOBMFF and use ISOBMFF to accumulate ortransmit PCC-encoded data. However, there has been no convention forstoring PCC-encoded data in an ISOBMFF file. In this embodiment, amethod of storing PCC-encoded data in an ISOBMFF file will be described.

FIG. 19 is a diagram showing a protocol stack in a case where a commonPCC codec NAL unit in an ISOBMFF file. Here, a common PCC codec NAL unitis stored in an ISOBMFF file. Although the NAL unit is common to PCCcodecs, a storage method for each codec (Carriage of Codec1, Carriage ofCodec2) is desirably prescribed, since a plurality of PCC codecs arestored in the NAL unit.

Next, a method of storing a common PCC NAL unit that supports aplurality of PCC codecs in an ISOBMFF file will be described. FIG. 20 isa diagram showing an example in which a common PCC NAL unit is stored inan ISOBMFF file for the storage method for codec 1 (Carriage of Coded).FIG. 21 is a diagram showing an example in which a common PCC NAL unitis stored in an ISOBMFF file for the storage method for codec 2(Carriage of Codec2).

Here, ftyp is information that is important for identification of thefile format, and a different identifier of ftyp is defined for eachcodec. When PCC-encoded data encoded in the first encoding method(encoding scheme) is stored in the file, ftyp is set to pcc1. WhenPCC-encoded data encoded in the second encoding method is stored in thefile, ftyp is set to pcc2.

Here, pcc1 indicates that PCC codec 1 (first encoding method) is used.pcc2 indicates that PCC codec2 (second encoding method) is used. Thatis, pcc1 and pcc2 indicate that the data is PCC (encodedthree-dimensional data (point cloud data)), and indicate the PCC codec(first encoding method or second encoding method).

In the following, a method of storing a NAL unit in an ISOBMFF file willbe described. The multiplexer analyzes the NAL unit header, anddescribes pcc1 in ftyp of ISOBMFF if pcc_codec_type=Codec1.

The multiplexer analyzes the NAL unit header, and describes pcc2 in ftypof ISOBMFF if pcc_codec_type=Codec2.

If pcc_nal_unit_type is metadata, the multiplexer stores the NAL unit inmoov or mdat in a predetermined manner, for example. Ifpcc_nal_unit_type is data, the multiplexer stores the NAL unit in moovor mdat in a predetermined manner, for example.

For example, the multiplexer may store the NAL unit size in the NALunit, as with HEVC.

According to this storage method, the demultiplexer (a system layer) candetermine whether the PCC-encoded data is encoded in the first encodingmethod or the second encoding method by analyzing ftyp included in thefile. Furthermore, as described above, by determining whether thePCC-encoded data is encoded in the first encoding method or the secondencoding method, the encoded data encoded in any one of the encodingmethods can be extracted from the data including both the encoded dataencoded in the encoding methods. Therefore, when transmitting theencoded data, the amount of data transmitted can be reduced. Inaddition, according to this storage method, different data (file)formats do not need to be set for the first encoding method and thesecond encoding method, and a common data format can be used for thefirst encoding method and the second encoding method.

Note that, when the identification information for the codec, such asftyp of ISOBMFF, is indicated in the metadata of the system layer, themultiplexer can store a NAL unit without pcc_nal_unit_type in theISOBMFF file.

Next, configurations and operations of the multiplexer of thethree-dimensional data encoding system (three-dimensional data encodingdevice) according to this embodiment and the demultiplexer of thethree-dimensional data decoding system (three-dimensional data decodingdevice) according to this embodiment will be described.

FIG. 22 is a diagram showing a configuration of first multiplexer 4710.First multiplexer 4710 includes file converter 4711 that generatesmultiplexed data (file) by storing encoded data generated by firstencoder 4630 and control information (NAL unit) in an ISOBMFF file.First multiplexer 4710 is included in multiplexer 4614 shown in FIG. 1 ,for example.

FIG. 23 is a diagram showing a configuration of first demultiplexer4720. First demultiplexer 4720 includes file inverse converter 4721 thatobtains encoded data and control information (NAL unit) from multiplexeddata (file) and outputs the obtained encoded data and controlinformation to first decoder 4640. First demultiplexer 4720 is includedin demultiplexer 4623 shown in FIG. 1 , for example.

FIG. 24 is a diagram showing a configuration of second multiplexer 4730.Second multiplexer 4730 includes file converter 4731 that generatesmultiplexed data (file) by storing encoded data generated by secondencoder 4650 and control information (NAL unit) in an ISOBMFF file.Second multiplexer 4730 is included in multiplexer 4614 shown in FIG. 1, for example.

FIG. 25 is a diagram showing a configuration of second demultiplexer4740. Second demultiplexer 4740 includes file inverse converter 4741that obtains encoded data and control information (NAL unit) frommultiplexed data (file) and outputs the obtained encoded data andcontrol information to second decoder 4660. Second demultiplexer 4740 isincluded in demultiplexer 4623 shown in FIG. 1 , for example.

FIG. 26 is a flowchart showing a multiplexing process by firstmultiplexer 4710. First, first multiplexer 4710 analyzes pcc_codec_typein the NAL unit header, thereby determining whether the codec used isthe first encoding method or the second encoding method (S4701).

When pcc_codec_type represents the second encoding method (if “secondencoding method” in S4702), first multiplexer 4710 does not process theNAL unit (S4703).

On the other hand, when pcc_codec_type represents the first encodingmethod (if “first encoding method” in S4702), first multiplexer 4710describes pcc1 in ftyp (S4704). That is, first multiplexer 4710describes information indicating that data encoded in the first encodingmethod is stored in the file in ftyp.

First multiplexer 4710 then analyzes pcc_nal_unit_type in the NAL unitheader, and stores the data in a box (moov or mdat, for example) in apredetermined manner suitable for the data type represented bypcc_nal_unit_type (S4705). First multiplexer 4710 then creates anISOBMFF file including the ftyp described above and the box describedabove (S4706).

FIG. 27 is a flowchart showing a multiplexing process by secondmultiplexer 4730. First, second multiplexer 4730 analyzes pcc_codec_typein the NAL unit header, thereby determining whether the codec used isthe first encoding method or the second encoding method (S4711).

When pcc_codec_type represents the second encoding method (if “secondencoding method” in S4712), second multiplexer 4730 describes pcc2 inftyp (S4713). That is, second multiplexer 4730 describes informationindicating that data encoded in the second encoding method is stored inthe file in ftyp.

Second multiplexer 4730 then analyzes pcc_nal_unit_type in the NAL unitheader, and stores the data in a box (moov or mdat, for example) in apredetermined manner suitable for the data type represented bypcc_nal_unit_type (S4714). Second multiplexer 4730 then creates anISOBMFF file including the ftyp described above and the box describedabove (S4715).

On the other hand, when pcc_codec_type represents the first encodingmethod (if “first encoding method” in S4712), second multiplexer 4730does not process the NAL unit (S4716).

Note that the process described above is an example in which PCC data isencoded in any one of the first encoding method and the second encodingmethod. First multiplexer 4710 and second multiplexer 4730 store adesired NAL unit in a file by identifying the codec type of the NALunit. Note that, when the identification information for the PCC codecis included in a location other than the NAL unit header, firstmultiplexer 4710 and second multiplexer 4730 may identify the codec type(first encoding method or second encoding method) based on theidentification information for the PCC codec included in the locationother than the NAL unit header in step S4701 or S4711.

When storing data in a file in step S4706 or S4714, first multiplexer4710 and second multiplexer 4730 may store the data in the file afterdeleting pcc_nal_unit_type from the NAL unit header.

FIG. 28 is a flowchart showing a process performed by firstdemultiplexer 4720 and first decoder 4640. First, first demultiplexer4720 analyzes ftyp in an ISOBMFF file (S4721). When the codecrepresented by ftyp is the second encoding method (pcc2) (if “secondencoding method” in S4722), first demultiplexer 4720 determines that thedata included in the payload of the NAL unit is data encoded in thesecond encoding method (S4723). First demultiplexer 4720 also transmitsthe result of the determination to first decoder 4640. First decoder4640 does not process the NAL unit (S4724).

On the other hand, when the codec represented by ftyp is the firstencoding method (pcc1) (if “first encoding method” in S4722), firstdemultiplexer 4720 determines that the data included in the payload ofthe NAL unit is data encoded in the first encoding method (S4725). Firstdemultiplexer 4720 also transmits the result of the determination tofirst decoder 4640.

First decoder 4640 identifies the data based on the determination thatpcc_nal_unit_type in the NAL unit header is the identifier of the NALunit for the first encoding method (S4726). First decoder 4640 thendecodes the PCC data using a decoding process for the first encodingmethod (S4727).

FIG. 29 is a flowchart showing a process performed by seconddemultiplexer 4740 and second decoder 4660. First, second demultiplexer4740 analyzes ftyp in an ISOBMFF file (S4731). When the codecrepresented by ftyp is the second encoding method (pcc2) (if “secondencoding method” in S4732), second demultiplexer 4740 determines thatthe data included in the payload of the NAL unit is data encoded in thesecond encoding method (S4733). Second demultiplexer 4740 also transmitsthe result of the determination to second decoder 4660.

Second decoder 4660 identifies the data based on the determination thatpcc_nal_unit_type in the NAL unit header is the identifier of the NALunit for the second encoding method (S4734). Second decoder 4660 thendecodes the PCC data using a decoding process for the second encodingmethod (S4735).

On the other hand, when the codec represented by ftyp is the firstencoding method (pcc1) (if “first encoding method” in S4732), seconddemultiplexer 4740 determines that the data included in the payload ofthe NAL unit is data encoded in the first encoding method (S4736).Second demultiplexer 4740 also transmits the result of the determinationto second decoder 4660. Second decoder 4660 does not process the NALunit (S4737).

As described above, for example, since the codec type of the NAL unit isidentified in first demultiplexer 4720 or second demultiplexer 4740, thecodec type can be identified in an early stage. Furthermore, a desiredNAL unit can be input to first decoder 4640 or second decoder 4660, andan unwanted NAL unit can be removed. In this case, the process of firstdecoder 4640 or second decoder 4660 analyzing the identificationinformation for the codec may be unnecessary. Note that a process ofreferring to the NAL unit type again and analyzing the identificationinformation for the codec may be performed by first decoder 4640 orsecond decoder 4660.

Furthermore, if pcc_nal_unit_type is deleted from the NAL unit header byfirst multiplexer 4710 or second multiplexer 4730, first demultiplexer4720 or second demultiplexer 4740 can output the NAL unit to firstdecoder 4640 or second decoder 4660 after adding pcc_nal_unit_type tothe NAL unit.

Embodiment 3

In Embodiment 3, a multiplexer and a demultiplexer that correspond toencoder 4670 and decoder 4680 ready for a plurality of codecs describedabove with regard to Embodiment 1 will be described. FIG. 30 is adiagram showing configurations of encoder 4670 and third multiplexer4750 according to this embodiment.

Encoder 4670 encodes point cloud data in both or one of the firstencoding method and the second encoding method. Encoder 4670 may changethe encoding method (between the first encoding method and the secondencoding method) on a point-cloud-data basis or on a frame basis.Alternatively, encoder 4670 may change the encoding method on the basisof an encodable unit.

Encoder 4670 generates encoded data (encoded stream) including theidentification information for a PCC codec.

Third multiplexer 4750 includes file converter 4751. File converter 4751converts a NAL unit output from encoder 4670 into a PCC data file. Fileconverter 4751 analyzes the codec identification information included inthe NAL unit header, and determines whether the PCC-encoded data is dataencoded in the first encoding method, data encoded in the secondencoding method, or data encoded in both the encoding methods. Fileconverter 4751 describes a brand name that allows codec identificationin ftyp. For example, when indicating the data is encoded in both theencoding methods, pcc3 is described in ftyp.

Note that, when encoder 4670 describes the PCC codec identificationinformation in a location other than the NAL unit, file converter 4751may determine the PCC codec (encoding method) based on theidentification information.

FIG. 31 is a diagram showing configurations of third demultiplexer 4760and decoder 4680 according to this embodiment.

Third demultiplexer 4760 includes file inverse converter 4761. Fileinverse converter 4761 analyzes ftyp included in a file, and determineswhether the PCC-encoded data is data encoded in the first encodingmethod, data encoded in the second encoding method, or data encoded inboth the encoding methods.

When the PCC-encoded data is data encoded in any one of the encodingmethods, the data is input to an appropriate one of first decoder 4640and second decoder 4660, and is not input to the other decoder. When thePCC-encoded data is data encoded in both the encoding methods, the datais input to decoder 4680 ready for both the encoding methods.

Decoder 4680 decodes the PCC-encoded data in both or one of the firstencoding method and the second encoding method.

FIG. 32 is a flowchart showing a process performed by third multiplexer4750 according to this embodiment.

First, third multiplexer 4750 analyzes pcc_codec_type in the NAL unitheader, thereby determining whether the codec(s) used is the firstencoding method, the second encoding method, or both the first encodingmethod and the second encoding method (S4741).

When the second encoding method is used (if Yes in S4742 and “secondencoding method” in S4743), third multiplexer 4750 describes pcc2 inftyp (S4744). That is, third multiplexer 4750 describes informationindicating that data encoded in the second encoding method is stored inthe file in ftyp.

Third multiplexer 4750 then analyzes pcc_nal_unit_type in the NAL unitheader, and stores the data in a box (moov or mdat, for example) in apredetermined manner suitable for the data type represented bypcc_nal_unit_type (S4745). Third multiplexer 4750 then creates anISOBMFF file including the ftyp described above and the box describedabove (S4746).

When the first encoding method is used (if Yes in S4742 and “firstencoding method” in S4743), third multiplexer 4750 describes pcc1 inftyp (S4747). That is, third multiplexer 4750 describes informationindicating that data encoded in the first encoding method is stored inthe file in ftyp.

Third multiplexer 4750 then analyzes pcc_nal_unit_type in the NAL unitheader, and stores the data in a box (moov or mdat, for example) in apredetermined manner suitable for the data type represented bypcc_nal_unit_type (S4748). Third multiplexer 4750 then creates anISOBMFF file including the ftyp described above and the box describedabove (S4746).

When both the first encoding method and the second encoding method areused (if No in S4742), third multiplexer 4750 describes pcc3 in ftyp(S4749). That is, third multiplexer 4750 describes informationindicating that data encoded in both the encoding methods is stored inthe file in ftyp.

Third multiplexer 4750 then analyzes pcc_nal_unit_type in the NAL unitheader, and stores the data in a box (moov or mdat, for example) in apredetermined manner suitable for the data type represented bypcc_nal_unit_type (S4750). Third multiplexer 4750 then creates anISOBMFF file including the ftyp described above and the box describedabove (S4746).

FIG. 33 is a flowchart showing a process performed by thirddemultiplexer 4760 and decoder 4680. First, third demultiplexer 4760analyzes ftyp included in an ISOBMFF file (S4761). When the codecrepresented by ftyp is the second encoding method (pcc2) (if Yes inS4762 and “second encoding method” in S4763), third demultiplexer 4760determines that the data included in the payload of the NAL unit is dataencoded in the second encoding method (S4764). Third demultiplexer 4760also transmits the result of the determination to decoder 4680.

Decoder 4680 identifies the data based on the determination thatpcc_nal_unit_type in the NAL unit header is the identifier of the NALunit for the second encoding method (S4765). Decoder 4680 then decodesthe PCC data using a decoding process for the second encoding method(S4766).

When the codec represented by ftyp is the first encoding method (pcc1)(if Yes in S4762 and “first encoding method” in S4763), thirddemultiplexer 4760 determines that the data included in the payload ofthe NAL unit is data encoded in the first encoding method (S4767). Thirddemultiplexer 4760 also transmits the result of the determination todecoder 4680.

Decoder 4680 identifies the data based on the determination thatpcc_nal_unit_type in the NAL unit header is the identifier of the NALunit for the first encoding method (S4768). Decoder 4680 then decodesthe PCC data using a decoding process for the first encoding method(S4769).

When ftyp indicates that both the encoding methods are used (pcc3) (ifNo in S4762), third demultiplexer 4760 determines that the data includedin the payload of the NAL unit is data encoded in both the firstencoding method and the second encoding method (S4770). Thirddemultiplexer 4760 also transmits the result of the determination todecoder 4680.

Decoder 4680 identifies the data based on the determination thatpcc_nal_unit_type in the NAL unit header is the identifier of the NALunit for the codecs described in pcc_codec_type (S4771). Decoder 4680then decodes the PCC data using decoding processes for both the encodingmethods (S4772). That is, decoder 4680 decodes the data encoded in thefirst encoding method using a decoding process for the first encodingmethod, and decodes the data encoded in the second encoding method usinga decoding process for the second encoding method.

In the following, variations of this embodiment will be described. Astypes of brands represented by ftyp, the types described below can beindicated by the identification information. Furthermore, a combinationof a plurality of the types described below can also be indicated by theidentification information.

The identification information may indicate whether the original dataobject yet to be PCC-encoded is a point cloud whose range is limited ora large point cloud whose range is not limited, such as map information.

The identification information may indicate whether the original datayet to be PCC-encoded is a static object or a dynamic object.

As described above, the identification information may indicate whetherthe PCC-encoded data is data encoded in the first encoding method ordata encoded in the second encoding method.

The identification information may indicate an algorithm used in the PCCencoding. Here, the “algorithm” means an encoding method that can beused in the first encoding method or the second encoding method, forexample.

The identification information may indicate a differentiation betweenmethods of storing the PCC-encoded data into an ISOBMFF file. Forexample, the identification information may indicate whether the storagemethod used is a storage method for accumulation or a storage method forreal-time transmission, such as dynamic streaming.

Although an example in which ISOBMFF is used as a file format has beendescribed in Embodiments 2 and 3, other formats can also be used. Forexample, the method according to this embodiment can also be used whenPCC-encoded data is stored in MPEG-2 TS Systems, MPEG-DASH, MMT, or RMP.

Although an example in which metadata, such as the identificationinformation, is stored in ftyp has been shown above, metadata can alsobe stored in a location other than ftyp. For example, the metadata maybe stored in moov.

As described above, a three-dimensional data storing device (orthree-dimensional data multiplexing device or three-dimensional dataencoding device) performs the process shown in FIG. 34 .

First, the three-dimensional data storing device (which includes firstmultiplexer 4710, second multiplexer 4730 or third multiplexer 4750, forexample) acquires one or more units (NAL units, for example) that storean encoded stream, which is encoded point cloud data (S4781). Thethree-dimensional data storing device then stores the one or more unitsin a file (an ISOBMFF file, for example) (S4782). In the storage(S4782), the three-dimensional data storing device also storesinformation indicating that the data stored in the file is encoded pointcloud data (pcc1, pcc2, or pcc3, for example) in the control information(ftyp, for example) (referred to also as signaling information) for thefile.

With such a configuration, a device that processes the file generated bythe three-dimensional data storing device can quickly determine whetherthe data stored in the file is encoded point cloud data or not byreferring to the control information for the file. Therefore, theprocessing amount of the device can be reduced, or the processing speedof the device can be increased.

For example, the information indicates the encoding method used for theencoding of the point cloud data among the first encoding method and thesecond encoding method. Note that the fact that the data stored in thefile is encoded point cloud data and the encoding method used for theencoding of the point cloud data among the first encoding method and thesecond encoding method may be indicated by a single piece of informationor different pieces of information.

With such a configuration, a device that processes the file generated bythe three-dimensional data storing device can quickly determine thecodec used for the data stored in the file by referring to the controlinformation for the file. Therefore, the processing amount of the devicecan be reduced, or the processing speed of the device can be increased.

For example, the first encoding method is a method (GPCC) that encodesgeometry information that represents the position of point cloud data asan N-ary tree (N represents an integer equal to or greater than 2) andencodes attribute information using the geometry information, and thesecond encoding method is a method (VPCC) that generates atwo-dimensional image from point cloud data and encodes thetwo-dimensional image in a video encoding method.

For example, the file described above is in conformity with ISOBMFF(ISO-based media file format).

For example, the three-dimensional data storing device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

As described above, a three-dimensional data acquisition device (orthree-dimensional data demultiplexing device or three-dimensional datadecoding device) performs the process shown in FIG. 35 .

The three-dimensional data acquisition device (which includes firstdemultiplexer 4720, second demultiplexer 4740, or third demultiplexer4760, for example) acquires a file (an ISOBMFF file, for example) thatstores one or more units (NAL units, for example) that store an encodedstream, which is encoded point cloud data (S4791). The three-dimensionaldata acquisition device acquires the one or more units from the file(S4792). The control information (ftyp, for example) for the fileincludes information indicating that the data stored in the file isencoded point cloud data (pcc1, pcc2, or pcc3, for example).

For example, the three-dimensional data acquisition device determineswhether the data stored in the file is encoded point cloud data or notby referring to the information. When the three-dimensional dataacquisition device determines that the data stored in the file isencoded point cloud data, the three-dimensional data acquisition devicegenerates point cloud data by decoding the encoded point cloud dataincluded in the one or more units. Alternatively, when thethree-dimensional data acquisition device determines that the datastored in the file is encoded point cloud data, the three-dimensionaldata acquisition device outputs information indicating that the dataincluded in the one or more units is encoded point cloud data to aprocessor in a subsequent stage (first decoder 4640, second decoder4660, or decoder 4680, for example) (or notifies a processor in asubsequent stage that the data included in the one or more units isencoded point cloud data).

With such a configuration, the three-dimensional data acquisition devicecan quickly determine whether the data stored in the file is encodedpoint cloud data or not by referring to the control information for thefile. Therefore, the processing amount of the three-dimensional dataacquisition device or a device in a subsequent stage can be reduced, orthe processing speed of the three-dimensional data acquisition device ora device in a subsequent stage can be increased.

For example, the information represents the encoding method used for theencoding among the first encoding method and the second encoding method.Note that the fact that the data stored in the file is encoded pointcloud data and the encoding method used for the encoding of the pointcloud data among the first encoding method and the second encodingmethod may be indicated by a single piece of information or differentpieces of information.

With such a configuration, the three-dimensional data acquisition devicecan quickly determine the codec used for the data stored in the file byreferring to the control information for the file. Therefore, theprocessing amount of the three-dimensional data acquisition device or adevice in a subsequent stage can be reduced, or the processing speed ofthe three-dimensional data acquisition device or a device in asubsequent stage can be increased.

For example, based on the information, the three-dimensional dataacquisition device acquires the data encoded in any one of the firstencoding method and the second encoding method from the encoded pointcloud data including the data encoded in the first encoding method andthe data encoded in the second encoding method.

For example, the first encoding method is a method (GPCC) that encodesgeometry information that represents the position of point cloud data asan N-ary tree (N represents an integer equal to or greater than 2) andencodes attribute information using the geometry information, and thesecond encoding method is a method (VPCC) that generates atwo-dimensional image from point cloud data and encodes thetwo-dimensional image in a video encoding method.

For example, the file described above is in conformity with ISOBMFF(ISO-based media file format).

For example, the three-dimensional data acquisition device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

Embodiment 4

In Embodiment 4, types of the encoded data (geometry information(geometry), attribute information (attribute), and additionalinformation (metadata)) generated by first encoder 4630 or secondencoder 4650 described above, a method of generating additionalinformation (metadata), and a multiplexing process in the multiplexerwill be described. The additional information (metadata) may be referredto as a parameter set or control information (signaling information).

In this embodiment, the dynamic object (three-dimensional point clouddata that varies with time) described above with reference to FIG. 4will be described, for example. However, the same method can also beused for the static object (three-dimensional point cloud dataassociated with an arbitrary time point).

FIG. 36 is a diagram showing configurations of encoder 4801 andmultiplexer 4802 in a three-dimensional data encoding device accordingto this embodiment. Encoder 4801 corresponds to first encoder 4630 orsecond encoder 4650 described above, for example. Multiplexer 4802corresponds to multiplexer 4634 or 4656 described above.

Encoder 4801 encodes a plurality of PCC (point cloud compression) framesof point cloud data to generate a plurality of pieces of encoded data(multiple compressed data) of geometry information, attributeinformation, and additional information.

Multiplexer 4802 integrates a plurality of types of data (geometryinformation, attribute information, and additional information) into aNAL unit, thereby converting the data into a data configuration thattakes data access in the decoding device into consideration.

FIG. 37 is a diagram showing a configuration example of the encoded datagenerated by encoder 4801. Arrows in the drawing indicate a dependenceinvolved in decoding of the encoded data. The source of an arrow dependson data of the destination of the arrow. That is, the decoding devicedecodes the data of the destination of an arrow, and decodes the data ofthe source of the arrow using the decoded data. In other words, “a firstentity depends on a second entity” means that data of the second entityis referred to (used) in processing (encoding, decoding, or the like) ofdata of the first entity.

First, a process of generating encoded data of geometry information willbe described. Encoder 4801 encodes geometry information of each frame togenerate encoded geometry data (compressed geometry data) for eachframe. The encoded geometry data is denoted by G(i). i denotes a framenumber or a time point of a frame, for example.

Furthermore, encoder 4801 generates a geometry parameter set (GPS(i))for each frame. The geometry parameter set includes a parameter that canbe used for decoding of the encoded geometry data. The encoded geometrydata for each frame depends on an associated geometry parameter set.

The encoded geometry data formed by a plurality of frames is defined asa geometry sequence. Encoder 4801 generates a geometry sequenceparameter set (referred to also as geometry sequence PS or geometry SPS)that stores a parameter commonly used for a decoding process for theplurality of frames in the geometry sequence. The geometry sequencedepends on the geometry SPS.

Next, a process of generating encoded data of attribute information willbe described. Encoder 4801 encodes attribute information of each frameto generate encoded attribute data (compressed attribute data) for eachframe. The encoded attribute data is denoted by A(i). FIG. 37 shows anexample in which there are attribute X and attribute Y, and encodedattribute data for attribute X is denoted by AX(i), and encodedattribute data for attribute Y is denoted by AY(i).

Furthermore, encoder 4801 generates an attribute parameter set (APS(i))for each frame. The attribute parameter set for attribute X is denotedby AXPS(i), and the attribute parameter set for attribute Y is denotedby AYPS(i). The attribute parameter set includes a parameter that can beused for decoding of the encoded attribute information. The encodedattribute data depends on an associated attribute parameter set.

The encoded attribute data formed by a plurality of frames is defined asan attribute sequence. Encoder 4801 generates an attribute sequenceparameter set (referred to also as attribute sequence PS or attributeSPS) that stores a parameter commonly used for a decoding process forthe plurality of frames in the attribute sequence. The attributesequence depends on the attribute SPS.

In the first encoding method, the encoded attribute data depends on theencoded geometry data.

FIG. 37 shows an example in which there are two types of attributeinformation (attribute X and attribute Y). When there are two types ofattribute information, for example, two encoders generate data andmetadata for the two types of attribute information. For example, anattribute sequence is defined for each type of attribute information,and an attribute SPS is generated for each type of attributeinformation.

Note that, although FIG. 37 shows an example in which there is one typeof geometry information, and there are two types of attributeinformation, the present invention is not limited thereto. There may beone type of attribute information or three or more types of attributeinformation. In such cases, encoded data can be generated in the samemanner. If the point cloud data has no attribute information, there maybe no attribute information. In such a case, encoder 4801 does not haveto generate a parameter set associated with attribute information.

Next, a process of generating encoded data of additional information(metadata) will be described. Encoder 4801 generates a PCC stream PS(referred to also as PCC stream PS or stream PS), which is a parameterset for the entire PCC stream. Encoder 4801 stores a parameter that canbe commonly used for a decoding process for one or more geometrysequences and one or more attribute sequences in the stream PS. Forexample, the stream PS includes identification information indicatingthe codec for the point cloud data and information indicating analgorithm used for the encoding, for example. The geometry sequence andthe attribute sequence depend on the stream PS.

Next, an access unit and a GOF will be described. In this embodiment,concepts of access unit (AU) and group of frames (GOF) are newlyintroduced.

An access unit is a basic unit for accessing data in decoding, and isformed by one or more pieces of data and one or more pieces of metadata.For example, an access unit is formed by geometry information and one ormore pieces of attribute information associated with a same time point.A GOF is a random access unit, and is formed by one or more accessunits.

Encoder 4801 generates an access unit header (AU header) asidentification information indicating the top of an access unit. Encoder4801 stores a parameter relating to the access unit in the access unitheader. For example, the access unit header includes a configuration ofor information on the encoded data included in the access unit. Theaccess unit header further includes a parameter commonly used for thedata included in the access unit, such as a parameter relating todecoding of the encoded data.

Note that encoder 4801 may generate an access unit delimiter thatincludes no parameter relating to the access unit, instead of the accessunit header. The access unit delimiter is used as identificationinformation indicating the top of the access unit. The decoding deviceidentifies the top of the access unit by detecting the access unitheader or the access unit delimiter.

Next, generation of identification information for the top of a GOF willbe described. As identification information indicating the top of a GOF,encoder 4801 generates a GOF header. Encoder 4801 stores a parameterrelating to the GOF in the GOF header. For example, the GOF headerincludes a configuration of or information on the encoded data includedin the GOF. The GOF header further includes a parameter commonly usedfor the data included in the GOF, such as a parameter relating todecoding of the encoded data.

Note that encoder 4801 may generate a GOF delimiter that includes noparameter relating to the GOF, instead of the GOF header. The GOFdelimiter is used as identification information indicating the top ofthe GOF. The decoding device identifies the top of the GOF by detectingthe GOF header or the GOF delimiter.

In the PCC-encoded data, the access unit is defined as a PCC frame unit,for example. The decoding device accesses a PCC frame based on theidentification information for the top of the access unit.

For example, the GOF is defined as one random access unit. The decodingdevice accesses a random access unit based on the identificationinformation for the top of the GOF. For example, if PCC frames areindependent from each other and can be separately decoded, a PCC framecan be defined as a random access unit.

Note that two or more PCC frames may be assigned to one access unit, anda plurality of random access units may be assigned to one GOF.

Encoder 4801 may define and generate a parameter set or metadata otherthan those described above. For example, encoder 4801 may generatesupplemental enhancement information (SEI) that stores a parameter (anoptional parameter) that is not always used for decoding.

Next, a configuration of encoded data and a method of storing encodeddata in a NAL unit will be described.

For example, a data format is defined for each type of encoded data.FIG. 38 is a diagram showing an example of encoded data and a NAL unit.

For example, as shown in FIG. 38 , encoded data includes a header and apayload. The encoded data may include length information indicating thelength (data amount) of the encoded data, the header, or the payload.The encoded data may include no header.

The header includes identification information for identifying the data,for example. The identification information indicates a data type or aframe number, for example.

The header includes identification information indicating a referencerelationship, for example. The identification information is stored inthe header when there is a dependence relationship between data, forexample, and allows an entity to refer to another entity. For example,the header of the entity to be referred to includes identificationinformation for identifying the data. The header of the referring entityincludes identification information indicating the entity to be referredto.

Note that, when the entity to be referred to or the referring entity canbe identified or determined from other information, the identificationinformation for identifying the data or identification informationindicating the reference relationship can be omitted.

Multiplexer 4802 stores the encoded data in the payload of the NAL unit.The NAL unit header includes pcc_nal_unit_type, which is identificationinformation for the encoded data. FIG. 39 is a diagram showing asemantics example of pcc_nal_unit_type.

As shown in FIG. 39 , when pcc_codec_type is codec 1 (Coded1: firstencoding method), values 0 to 10 of pcc_nal_unit_type are assigned toencoded geometry data (Geometry), encoded attribute X data (AttributeX),encoded attribute Y data (AttributeY), geometry PS (Geom. PS), attributeXPS (AttrX. S), attribute YPS (AttrY. PS), geometry SPS (GeometrySequence PS), attribute X SPS (AttributeX Sequence PS), attribute Y SPS(AttributeY Sequence PS), AU header (AU Header), and GOF header (GOFHeader) in codec 1. Values of 11 and greater are reserved in codec 1.

When pcc_codec_type is codec 2 (Codec2: second encoding method), valuesof 0 to 2 of pcc_nal_unit_type are assigned to data A (DataA), metadataA (MetaDataA), and metadata B (MetaDataB) in the codec. Values of 3 andgreater are reserved in codec 2.

Next, an order of transmission of data will be described. In thefollowing, restrictions on the order of transmission of NAL units willbe described.

Multiplexer 4802 transmits NAL units on a GOF basis or on an AU basis.Multiplexer 4802 arranges the GOF header at the top of a GOF, andarranges the AU header at the top of an AU.

In order to allow the decoding device to decode the next AU and thefollowing AUs even when data is lost because of a packet loss or thelike, multiplexer 4802 may arrange a sequence parameter set (SPS) ineach AU.

When there is a dependence relationship for decoding between encodeddata, the decoding device decodes the data of the entity to be referredto and then decodes the data of the referring entity. In order to allowthe decoding device to perform decoding in the order of receptionwithout rearranging the data, multiplexer 4802 first transmits the dataof the entity to be referred to.

FIG. 40 is a diagram showing examples of the order of transmission ofNAL units. FIG. 40 shows three examples, that is, geometryinformation-first order, parameter-first order, and data-integratedorder.

The geometry information-first order of transmission is an example inwhich information relating to geometry information is transmittedtogether, and information relating to attribute information istransmitted together. In the case of this order of transmission, thetransmission of the information relating to the geometry informationends earlier than the transmission of the information relating to theattribute information.

For example, according to this order of transmission is used, when thedecoding device does not decode attribute information, the decodingdevice may be able to have an idle time since the decoding device canomit decoding of attribute information. When the decoding device isrequired to decode geometry information early, the decoding device maybe able to decode geometry information earlier since the decoding deviceobtains encoded data of the geometry information earlier.

Note that, although in FIG. 40 the attribute X SPS and the attribute YSPS are integrated and shown as the attribute SPS, the attribute X SPSand the attribute Y SPS may be separately arranged.

In the parameter set-first order of transmission, a parameter set isfirst transmitted, and data is then transmitted.

As described above, as far as the restrictions on the order oftransmission of NAL units are met, multiplexer 4802 can transmit NALunits in any order. For example, order identification information may bedefined, and multiplexer 4802 may have a function of transmitting NALunits in a plurality of orders. For example, the order identificationinformation for NAL units is stored in the stream PS.

The three-dimensional data decoding device may perform decoding based onthe order identification information. The three-dimensional datadecoding device may indicate a desired order of transmission to thethree-dimensional data encoding device, and the three-dimensional dataencoding device (multiplexer 4802) may control the order of transmissionaccording to the indicated order of transmission.

Note that multiplexer 4802 can generate encoded data having a pluralityof functions merged to each other as in the case of the data-integratedorder of transmission, as far as the restrictions on the order oftransmission are met. For example, as shown in FIG. 40 , the GOF headerand the AU header may be integrated, or AXPS and AYPS may be integrated.In such a case, an identifier that indicates data having a plurality offunctions is defined in pcc_nal_unit_type.

In the following, variations of this embodiment will be described. Thereare levels of PSs, such as a frame-level PS, a sequence-level PS, and aPCC sequence-level PS. Provided that the PCC sequence level is a higherlevel, and the frame level is a lower level, parameters can be stored inthe manner described below.

The value of a default PS is indicated in a PS at a higher level. If thevalue of a PS at a lower level differs from the value of the PS at ahigher level, the value of the PS is indicated in the PS at the lowerlevel. Alternatively, the value of the PS is not described in the PS atthe higher level but is described in the PS at the lower level.Alternatively, information indicating whether the value of the PS isindicated in the PS at the lower level, at the higher level, or at boththe levels is indicated in both or one of the PS at the lower level andthe PS at the higher level. Alternatively, the PS at the lower level maybe merged with the PS at the higher level. If the PS at the lower leveland the PS at the higher level overlap with each other, multiplexer 4802may omit transmission of one of the PSs.

Note that encoder 4801 or multiplexer 4802 may divide data into slicesor tiles and transmit each of the divided slices or tiles as divideddata. The divided data includes information for identifying the divideddata, and a parameter used for decoding of the divided data is includedin the parameter set. In this case, an identifier that indicates thatthe data is data relating to a tile or slice or data storing a parameteris defined in pcc_nal_unit_type. In the following, a process relating toorder identification information will be described. FIG. 41 is aflowchart showing a process performed by the three-dimensional dataencoding device (encoder 4801 and multiplexer 4802) that involves theorder of transmission of NAL units.

First, the three-dimensional data encoding device determines the orderof transmission of NAL units (geometry information-first or parameterset-first) (S4801). For example, the three-dimensional data encodingdevice determines the order of transmission based on a specificationfrom a user or an external device (the three-dimensional data decodingdevice, for example).

If the determined order of transmission is geometry information-first(if “geometry information-first” in S4802), the three-dimensional dataencoding device sets the order identification information included inthe stream PS to geometry information-first (S4803). That is, in thiscase, the order identification information indicates that the NAL unitsare transmitted in the geometry information-first order. Thethree-dimensional data encoding device then transmits the NAL units inthe geometry information-first order (S4804).

On the other hand, if the determined order of transmission is parameterset-first (if “parameter set-first” in S4802), the three-dimensionaldata encoding device sets the order identification information includedin the stream PS to parameter set-first (S4805). That is, in this case,the order identification information indicates that the NAL units aretransmitted in the parameter set-first order. The three-dimensional dataencoding device then transmits the NAL units in the parameter set-firstorder (S4806).

FIG. 42 is a flowchart showing a process performed by thethree-dimensional data decoding device that involves the order oftransmission of NAL units. First, the three-dimensional data decodingdevice analyzes the order identification information included in thestream PS (S4811).

If the order of transmission indicated by the order identificationinformation is geometry information-first (if “geometryinformation-first” in S4812), the three-dimensional data decoding devicedecodes the NAL units based on the determination that the order oftransmission of the NAL units is geometry information-first (S4813).

On the other hand, if the order of transmission indicated by the orderidentification information is parameter set-first (if “parameterset-first” in S4812), the three-dimensional data decoding device decodesthe NAL units based on the determination that the order of transmissionof the NAL units is parameter set-first (S4814).

For example, if the three-dimensional data decoding device does notdecode attribute information, in step S4813, the three-dimensional datadecoding device does not obtain the entire NAL units but can obtain apart of a NAL unit relating to the geometry information and decode theobtained NAL unit to obtain the geometry information.

Next, a process relating to generation of an AU and a GOF will bedescribed. FIG. 43 is a flowchart showing a process performed by thethree-dimensional data encoding device (multiplexer 4802) that relatesto generation of an AU and a GOF in multiplexing of NAL units.

First, the three-dimensional data encoding device determines the type ofthe encoded data (S4821). Specifically, the three-dimensional dataencoding device determines whether the encoded data to be processed isAU-first data, GOF-first data, or other data.

If the encoded data is GOF-first data (if “GOF-first” in S4822), thethree-dimensional data encoding device generates NAL units by arranginga GOF header and an AU header at the top of the encoded data belongingto the GOF (S4823).

If the encoded data is AU-first data (if “AU-first” in S4822), thethree-dimensional data encoding device generates NAL units by arrangingan AU header at the top of the encoded data belonging to the AU (S4824).

If the encoded data is neither GOF-first data nor AU-first data (if“other than GOF-first and AU-first” in S4822), the three-dimensionaldata encoding device generates NAL units by arranging the encoded datato follow the AU header of the AU to which the encoded data belongs(S4825).

Next, a process relating to access to an AU and a GOF will be described.FIG. 44 is a flowchart showing a process performed by thethree-dimensional data decoding device that involves accessing to an AUand a GOF in demultiplexing of a NAL unit.

First, the three-dimensional data decoding device determines the type ofthe encoded data included in the NAL unit by analyzing nal_unit_type inthe NAL unit (S4831). Specifically, the three-dimensional data decodingdevice determines whether the encoded data included in the NAL unit isAU-first data, GOF-first data, or other data.

If the encoded data included in the NAL unit is GOF-first data (if“GOF-first” in S4832), the three-dimensional data decoding devicedetermines that the NAL unit is a start position of random access,accesses the NAL unit, and starts the decoding process (S4833).

If the encoded data included in the NAL unit is AU-first data (if“AU-first” in S4832), the three-dimensional data decoding devicedetermines that the NAL unit is AU-first, accesses the data included inthe NAL unit, and decodes the AU (S4834).

If the encoded data included in the NAL unit is neither GOF-first datanor AU-first data (if “other than GOF-first and AU-first” in S4832), thethree-dimensional data decoding device does not process the NAL unit.

As described above, the three-dimensional data encoding device performsthe process shown in FIG. 45 . The three-dimensional data encodingdevice encodes time-series three-dimensional data (point cloud data on adynamic object, for example). The three-dimensional data includesgeometry information and attribute information associated with each timepoint.

First, the three-dimensional data encoding device encodes the geometryinformation (S4841). The three-dimensional data encoding device thenencodes the attribute information to be processed by referring to thegeometry information associated with the same time point as theattribute information to be processed (S4842). Here, as shown in FIG. 37, the geometry information and the attribute information associated withthe same time point form an access unit (AU). That is, thethree-dimensional data encoding device encodes the attribute informationto be processed by referring to the geometry information included in thesame access unit as the attribute information to be processed.

In this way, the three-dimensional data encoding device can takeadvantage of the access unit to facilitate control of reference inencoding. Therefore, the three-dimensional data encoding device canreduce the processing amount of the encoding process.

For example, the three-dimensional data encoding device generates abitstream including the encoded geometry information (encoded geometrydata), the encoded attribute information (encoded attribute data), andinformation indicating the geometry information of the entity to bereferred to when encoding the attribute information to be processed.

For example, the bitstream includes a geometry parameter set (geometryPS) that includes control information for the geometry informationassociated with each time point and an attribute parameter set(attribute PS) that includes control information for the attributeinformation associated with each time point.

For example, the bitstream includes a geometry sequence parameter set(geometry SPS) that includes control information that is common to aplurality of pieces of geometry information associated with differenttime points and attribute sequence parameter set (attribute SPS) thatincludes control information that is common to a plurality of pieces ofattribute information associated with different time points.

For example, the bitstream includes a stream parameter set (stream PS)that includes control information that is common to a plurality ofpieces of geometry information associated with different time points anda plurality of pieces of attribute information associated with differenttime points.

For example, the bitstream includes an access unit header (AU header)that includes control information that is common in an access unit.

For example, the three-dimensional data encoding device performsencoding in such a manner that groups of frames (GOFs) formed by one ormore access units can be independently decoded. That is, the GOF is arandom access unit.

For example, the bitstream includes a GOF header that includes controlinformation that is common in a GOF.

For example, the three-dimensional data encoding device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

As described above, the three-dimensional data decoding device performsthe process shown in FIG. 46 . The three-dimensional data decodingdevice decodes time-series three-dimensional data (point cloud data on adynamic object, for example). The three-dimensional data includesgeometry information and attribute information associated with each timepoint. The geometry information and the attribute information associatedwith the same time point forms an access unit (AU).

First, the three-dimensional data decoding device decodes the bitstreamto obtain the geometry information (S4851). That is, thethree-dimensional data decoding device generates the geometryinformation by decoding the encoded geometry information (encodedgeometry data) included in the bitstream.

The three-dimensional data decoding device then decodes the bitstream toobtain the attribute information to be processed by referring to thegeometry information associated with the same time point as theattribute information to be processed (S4852). That is, thethree-dimensional data decoding device generates the attributeinformation by decoding the encoded attribute information (encodedattribute data) included in the bitstream. In this process, thethree-dimensional data decoding device refers to the decoded geometryinformation included in the access unit as the attribute information.

In this way, the three-dimensional data decoding device can takeadvantage of the access unit to facilitate control of reference indecoding. Therefore, the three-dimensional data decoding device canreduce the processing amount of the decoding process.

For example, the three-dimensional data decoding device obtains, fromthe bitstream, information indicating the geometry information of theentity to be referred to when decoding the attribute information to beprocessed, and decodes the attribute information to be processed byreferring to the geometry information of the entity to be referred toindicated by the obtained information.

For example, the bitstream includes a geometry parameter set (geometryPS) that includes control information for the geometry informationassociated with each time point and an attribute parameter set(attribute PS) that includes control information for the attributeinformation associated with each time point. That is, thethree-dimensional data decoding device uses the control informationincluded in the geometry parameter set associated with the time point tobe intended for processing to decode the geometry information associatedwith the time point intended for processing, and uses the controlinformation included in the attribute parameter set associated with thetime point intended for processing to decode the attribute informationassociated with the time point intended for processing.

For example, the bitstream includes a geometry sequence parameter set(geometry SPS) that includes control information that is common to aplurality of pieces of geometry information associated with differenttime points and an attribute sequence parameter set (attribute SPS) thatincludes control information that is common to a plurality of pieces ofattribute information associated with different time points. That is,the three-dimensional data decoding device uses the control informationincluded in the geometry sequence parameter set to decode a plurality ofpieces of geometry information associated with different time points,and uses the control information included in the attribute sequenceparameter set to decode a plurality of pieces of attribute informationassociated with different time points.

For example, the bitstream includes a stream parameter set (stream PS)that includes control information that is common to a plurality ofpieces of geometry information associated with different time points anda plurality of pieces of attribute information associated with differenttime points. That is, the three-dimensional data decoding device usesthe control information included in the stream parameter set to decode aplurality of pieces of geometry information associated with differenttime points and a plurality of pieces of attribute informationassociated with different time points.

For example, the bitstream includes an access unit header (AU header)that includes control information that is common in an access unit. Thatis, the three-dimensional data decoding device uses the controlinformation included in the access unit header to decode the geometryinformation and the attribute information included in the access unit.

For example, the three-dimensional data decoding device independentlydecodes groups of frames (GOFs) formed by one or more access units. Thatis, the GOF is a random access unit.

For example, the bitstream includes a GOF header that includes controlinformation that is common in a GOF. That is, the three-dimensional datadecoding device decodes the geometry information and the attributeinformation included in the GOF using the control information includedin the GOF header.

For example, the three-dimensional data decoding device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

Embodiment 5

Although there are tools for data dividing, such as the slice or thetile, in HEVC encoding in order to make parallel processing in adecoding device possible, there are no such tools yet in PCC (PointCloud Compression) encoding.

In PCC, various data dividing methods can be considered according toparallel processing, compression efficiency, and compression algorithms.Here, the definitions of slice and tile, the data structure, and thetransmission/reception methods will be described.

FIG. 47 is a block diagram illustrating the configuration of firstencoder 4910 included in a three-dimensional data encoding deviceaccording to the present embodiment. First encoder 4910 generatesencoded data (an encoded stream) by encoding point cloud data with afirst encoding method (GPCC (Geometry based PCC)). First encoder 4910includes divider 4911, a plurality of geometry information encoders4912, a plurality of attribute information encoders 4913, additionalinformation encoder 4914, and multiplexer 4915.

Divider 4911 generates a plurality of divided data by dividing pointcloud data. Specifically, divider 4911 generates a plurality of divideddata by dividing the space of point cloud data into a plurality ofsubspaces. Here, the subspaces are one of tiles and slices, or acombination of tiles and slices. More specifically, point cloud dataincludes geometry information, attribute information, and additionalinformation. Divider 4911 divides geometry information into a pluralityof divided geometry information, and divides attribute information intoa plurality of divided attribute information. Also, divider 4911generates additional information about division.

A plurality of geometry information encoders 4912 generate a pluralityof encoded geometry information by encoding the plurality of dividedgeometry information. For example, the plurality of geometry informationencoders 4912 process the plurality of divided geometry information inparallel.

The plurality of attribute information encoders 4913 generate aplurality of encoded attribute information by encoding the plurality ofdivided attribute information. For example, the plurality of attributeinformation encoders 4913 process the plurality of divided attributeinformation in parallel.

Additional information encoder 4914 generates encoded additionalinformation by encoding the additional information included in pointcloud data, and the additional information about data dividing generatedby divider 4911 at the time of division.

Multiplexer 4915 generates encoded data (an encoded stream) bymultiplexing the plurality of encoded geometry information, theplurality of encoded attribute information, and the encoded additionalinformation, and transmits the generated encoded data. Furthermore, theencoded additional information is used at the time of decoding.

Note that, although FIG. 47 illustrates the example in which therespective numbers of geometry information encoders 4912 and attributeinformation encoders 4913 are two, the respective numbers of geometryinformation encoders 4912 and attribute information encoders 4913 may beone, or may be three or more. Furthermore, the plurality of divided datamay be processed in parallel in the same chip, such as a plurality ofcores in a CPU, may be processed in parallel by the respective cores ofa plurality of chips, or may be processed in parallel by the pluralityof cores of a plurality of chips.

FIG. 48 is a block diagram illustrating the configuration of firstdecoder 4920. First decoder 4920 restores point cloud data by decodingthe encoded data (encoded stream) generated by encoding the point clouddata with the first encoding method (GPCC). First decoder 4920 includesdemultiplexer 4921, a plurality of geometry information decoders 4922, aplurality of attribute information decoders 4923, additional informationdecoder 4924, and combiner 4925.

Demultiplexer 4921 generates a plurality of encoded geometryinformation, a plurality of encoded attribute information, and encodedadditional information by demultiplexing the encoded data (encodedstream).

The plurality of geometry information decoders 4922 generate a pluralityof divided geometry information by decoding the plurality of encodedgeometry information. For example, the plurality of geometry informationdecoders 4922 process the plurality of encoded geometry information inparallel.

The plurality of attribute information decoders 4923 generate aplurality of divided attribute information by decoding the plurality ofencoded attribute information. For example, the plurality of attributeinformation decoders 4923 process the plurality of encoded attributeinformation in parallel.

Additional information decoder 4924 generates additional information bydecoding the encoded additional information.

Combiner 4925 generates geometry information by combining the pluralityof divided geometry information by using the additional information.Combiner 4925 generates attribute information by combining the pluralityof divided attribute information by using the additional information.

Note that, although FIG. 48 illustrates the example in which therespective numbers of geometry information decoders 4922 and attributeinformation decoders 4923 are two, the respective numbers of geometryinformation decoders 4922 and attribute information decoders 4923 may beone, or may be three or more. Furthermore, the plurality of divided datamay be processed in parallel in the same chip, such as a plurality ofcores in a CPU, may be processed in parallel by the respective cores ofa plurality of chips, or may be processed in parallel by the pluralityof cores of a plurality of chips.

Next, the configuration of divider 4911 will be described. FIG. 49 is ablock diagram of divider 4911. Divider 4911 includes slice divider 4931,geometry information tile divider (geometry tile divider) 4932, andattribute information tile divider (attribute tile divider) 4933.

Slice divider 4931 generates a plurality of slice geometry informationby dividing geometry information (position or geometry) into slices.Also, slice divider 4931 generates a plurality of slice attributeinformation by dividing attribute information (attribute) into slices.Furthermore, slice divider 4931 outputs slice additional information(SliceMetaData) including the information related to slice dividing andthe information generated in the slice dividing.

Geometry information tile divider 4932 generates a plurality of dividedgeometry information (a plurality of tile geometry information) bydividing the plurality of slice geometry information into tiles. Also,geometry information tile divider 4932 outputs geometry tile additionalinformation (geometry tile metadata) including the information relatedto tile dividing of geometry information, and the information generatedin the tile dividing of the geometry information.

Attribute information tile divider 4933 generates a plurality of dividedattribute information (a plurality of tile attribute information) bydividing the plurality of slice attribute information into tiles. Also,attribute information tile divider 4933 outputs attribute tileadditional information (attribute tile metadata) including theinformation related to tile dividing of attribute information, and theinformation generated in the tile dividing of the attribute information.

Note that the number of slices or tiles to be divided is one or more.That is, slice or tile dividing may not be performed.

Note that, although the example in which tile dividing is performedafter slice dividing has been illustrated here, slice dividing may beperformed after tile dividing. Furthermore, a new division type may bedefined in addition to the slice and the tile, and dividing may beperformed with three or more division types.

Hereinafter, the dividing method for point cloud data will be described.FIG. 50 is a diagram illustrating an example of slice and tile dividing.

First, the method for slice dividing will be described. Divider 4911divides three-dimensional point cloud data into arbitrary point cloudson a slice-by-slice basis. In slice dividing, divider 4911 does notdivide the geometry information and the attribute informationconstituting points, but collectively divides the geometry informationand the attribute information. That is, divider 4911 performs slicedividing so that the geometry information and the attribute informationof an arbitrary point belong to the same slice. Note that, as long asthese are followed, the number of divisions and the dividing method maybe any number and any method. Furthermore, the minimum unit of divisionis a point. For example, the numbers of divisions of geometryinformation and attribute information are the same. For example, athree-dimensional point corresponding to geometry information afterslice dividing, and a three-dimensional point corresponding to attributeinformation are included in the same slice.

Also, divider 4911 generates slice additional information, which isadditional information related to the number of divisions and thedividing method at the time of slice dividing. The slice additionalinformation is the same for geometry information and attributeinformation. For example, the slice additional information includes theinformation indicating the reference coordinate position, size, or sidelength of a bounding box after division. Also, the slice additionalinformation includes the information indicating the number of divisions,the division type, etc.

Next, the method for tile dividing will be described. Divider 4911divides the data divided into slices into slice geometry information (Gslice) and slice attribute information (A slice), and divides each ofthe slice geometry information and the slice attribute information on atile-by-tile basis.

Note that, although FIG. 50 illustrates the example in which division isperformed with an octree structure, the number of divisions and thedividing method may be any number and any method.

Also, divider 4911 may divide geometry information and attributeinformation with different dividing methods, or may divide geometryinformation and attribute information with the same dividing method.Additionally, divider 4911 may divide a plurality of slices into tileswith different dividing methods, or may divide a plurality of slicesinto tiles with the same dividing method.

Furthermore, divider 4911 generates tile additional information relatedto the number of divisions and the dividing method at the time of tiledividing. The tile additional information (geometry tile additionalinformation and attribute tile additional information) is separate forgeometry information and attribute information. For example, the tileadditional information includes the information indicating the referencecoordinate position, size, or side length of a bounding box afterdivision. Additionally, the tile additional information includes theinformation indicating the number of divisions, the division type, etc.

Next, an example of the method of dividing point cloud data into slicesor tiles will be described. As the method for slice or tile dividing,divider 4911 may use a predetermined method, or may adaptively switchmethods to be used according to point cloud data.

At the time of slice dividing, divider 4911 divides a three-dimensionalspace by collectively handling geometry information and attributeinformation. For example, divider 4911 determines the shape of anobject, and divides a three-dimensional space into slices according tothe shape of the object. For example, divider 4911 extracts objects suchas trees or buildings, and performs division on an object-by-objectbasis. For example, divider 4911 performs slice dividing so that theentirety of one or a plurality of objects are included in one slice.Alternatively, divider 4911 divides one object into a plurality ofslices.

In this case, the encoding device may change the encoding method foreach slice, for example. For example, the encoding device may use ahigh-quality compression method for a specific object or a specific partof the object. In this case, the encoding device may store theinformation indicating the encoding method for each slice in additionalinformation (metadata).

Also, divider 4911 may perform slice dividing so that each slicecorresponds to a predetermined coordinate space based on map informationor geometry information.

At the time of tile dividing, divider 4911 separately divides geometryinformation and attribute information. For example, divider 4911 dividesslices into tiles according to the data amount or the processing amount.For example, divider 4911 determines whether the data amount of a slice(for example, the number of three-dimensional points included in aslice) is greater than a predetermined threshold value. When the dataamount of the slice is greater than the threshold value, divider 4911divides slices into tiles. When the data amount of the slice is lessthan the threshold value, divider 4911 does not divide slices intotiles.

For example, divider 4911 divides slices into tiles so that theprocessing amount or processing time in the decoding device is within acertain range (equal to or less than a predetermined value).Accordingly, the processing amount per tile in the decoding devicebecomes constant, and distributed processing in the decoding devicebecomes easy.

Additionally, when the processing amount is different between geometryinformation and attribute information, for example, when the processingamount of geometry information is greater than the processing amount ofattribute information, divider 4911 makes the number of divisions ofgeometry information larger than the number of divisions of attributeinformation.

Furthermore, for example, when geometry information may be decoded anddisplayed earlier, and attribute information may be slowly decoded anddisplayed later in the decoding device according to contents, divider4911 may make the number of divisions of geometry information largerthan the number of divisions of attribute information. Accordingly,since the decoding device can increase the parallel number of geometryinformation, it is possible to make the processing of geometryinformation faster than the processing of attribute information.

Note that the decoding device does not necessarily have to processsliced or tiled data in parallel, and may determine whether or not toprocess them in parallel according to the number or capability ofdecoding processors.

By performing division with the method as described above, it ispossible to achieve adaptive encoding according to contents or objects.Also, parallel processing in decoding processing can be achieved.Accordingly, the flexibility of a point cloud encoding system or a pointcloud decoding system is improved.

FIG. 51 is a diagram illustrating dividing pattern examples of slicesand tiles. DU in the diagram is a data unit (DataUnit), and indicatesthe data of a tile or a slice. Additionally, each DU includes a sliceindex (SliceIndex) and a tile index (TileIndex). The top right numericalvalue of a DU in the diagram indicates the slice index, and the bottomleft numerical value of the DU indicates the tile index.

In Pattern 1, in slice dividing, the number of divisions and thedividing method are the same for G slice and A slice. In tile dividing,the number of divisions and the dividing method for G slice aredifferent from the number of divisions and the dividing method for Aslice. Additionally, the same number of divisions and dividing methodare used among a plurality of G slices. The same number of divisions anddividing method are used among a plurality of A slices.

In Pattern 2, in slice dividing, the number of divisions and thedividing method are the same for G slice and A slice. In tile dividing,the number of divisions and the dividing method for G slice aredifferent from the number of divisions and the dividing method for Aslice. Additionally, the number of divisions and the dividing method aredifferent among a plurality of G slices. The number of divisions and thedividing method are different among a plurality of A slices.

Next, the encoding method for divided data will be described. Thethree-dimensional data encoding device (first encoder 4910) encodes eachof divided data. When encoding attribute information, thethree-dimensional data encoding device generates, as additionalinformation, dependency information indicating based on whichconfiguration information (geometry information, additional information,or other attribute information) encoding has been performed. That is,the dependency information indicates, for example, the configurationinformation of a reference destination (dependence destination). In thiscase, the three-dimensional data encoding device generates thedependency information based on the configuration informationcorresponding to the divided shape of attribute information. Note thatthe three-dimensional data encoding device may generate the dependencyinformation based on the configuration information corresponding to aplurality of divided shapes.

Dependency information may be generated by the three-dimensional dataencoding device, and the generated dependency information may betransmitted to the three-dimensional decoding device. Alternatively, thethree-dimensional decoding device may generate dependency information,and the three-dimensional data encoding device may not transmit thedependency information. Furthermore, the dependency used by thethree-dimensional data encoding device may be defined in advance, andthe three-dimensional data encoding device may not transmit thedependency information.

FIG. 52 is a diagram illustrating an example of dependency of each data.The heads of arrows in the diagram indicate dependence destinations, andthe origins of the arrows indicate dependence sources. Thethree-dimensional data decoding device decodes data in the order of adependence destination to a dependence source. Additionally, the dataindicated by solid lines in the diagram is data that is actuallytransmitted, and the data indicated by dotted lines is data that is nottransmitted.

Furthermore, in the diagram, G indicates geometry information, and Aindicates attribute information. G_(s1) indicates the geometryinformation of slice number 1, and G_(s2) indicates the geometryinformation of slice number 2. G_(s1t1) indicates the geometryinformation of slice number 1 and tile number 1, G_(s1t2) indicates thegeometry information of slice number 1 and tile number 2, G_(s2t1)indicates the geometry information of slice number 2 and tile number 1,and G_(s2t2) indicates the geometry information of slice number 2 andtile number 2. Similarly, A_(s1) indicates the attribute information ofslice number 1, and A_(s2) indicates the attribute information of slicenumber 2. A_(s1t1) indicates the attribute information of slice number 1and tile number 1, A_(s1t2) indicates the attribute information of slicenumber 1 and tile number 2, A_(s2t1) indicates the attribute informationof slice number 2 and tile number 1, and A_(s2t2) indicates theattribute information of slice number 2 and tile number 2.

Mslice indicates slice additional information, MGtile indicates geometrytile additional information, and MAtile indicates attribute tileadditional information. D_(s1t1) indicates the dependency information ofattribute information A_(s1t1), and D_(s2t1) indicates the dependencyinformation of attribute information A_(s2t1).

Additionally, the three-dimensional data encoding device may rearrangedata in a decoding order, so that it is unnecessary to rearrange data inthe three-dimensional data decoding device. Note that data may berearranged in the three-dimensional data decoding device, or data may berearranged in both the three-dimensional data encoding device and thethree-dimensional data decoding device.

FIG. 53 is a diagram illustrating an example of the data decoding order.In the example of FIG. 53 , decoding is sequentially performed from thedata on the left. For those data in dependency, the three-dimensionaldata decoding device decodes the data of a dependence destination first.For example, the three-dimensional data encoding device rearranges datain advance to be in this order, and transmits the data. Note that, aslong as it is the order in which the data of dependence destinationsbecome first, it may be any kind of order. Additionally, thethree-dimensional data encoding device may transmit additionalinformation and dependency information before data.

FIG. 54 is a flowchart illustrating the flow of processing by thethree-dimensional data encoding device. First, the three-dimensionaldata encoding device encodes the data of a plurality of slices or tilesas described above (S4901). Next, as illustrated in FIG. 53 , thethree-dimensional data encoding device rearranges the data so that thedata of dependence destinations become first (S4902). Next, thethree-dimensional data encoding device multiplexes the rearranged data(forms the rearranged data into a NAL unit) (S4903).

Next, the configuration of combiner 4925 included in first decoder 4920will be described. FIG. 55 is a block diagram illustrating theconfiguration of combiner 4925. Combiner 4925 includes geometryinformation tile combiner (geometry tile combiner) 4941, attributeinformation tile combiner (attribute tile combiner) 4942, and a slicecombiner.

Geometry information tile combiner 4941 generates a plurality of slicegeometry information by combining a plurality of divided geometryinformation by using geometry tile additional information. Attributeinformation tile combiner 4942 generates a plurality of slice attributeinformation by combining a plurality of divided attribute information byusing attribute tile additional information.

Slice combiner 4943 generates geometry information by combining theplurality of slice geometry information by using slice additionalinformation. Additionally, slice combiner 4943 generates attributeinformation by combining the plurality of slice attribute information byusing slice additional information.

Note that the number of slices or tiles to be divided is one or more.That is, slice or tile dividing may not be performed.

Furthermore, although the example in which tile dividing is performedafter slice dividing has been illustrated here, slice dividing may beperformed after tile dividing. Furthermore, a new division type may bedefined in addition to the slice and the tile, and dividing may beperformed with three or more division types.

Next, the configuration of encoded data divided into slices or dividedinto tiles, and the storing method (multiplexing method) of the encodeddata into a NAL unit will be described. FIG. 56 is a diagramillustrating the configuration of encoded data, and the storing methodof the encoded data into a NAL unit.

Encoded data (divided geometry information and divided attributeinformation) is stored in the payload of a NAL unit.

Encoded data includes a header and a payload. The header includesidentification information for specifying the data included in thepayload. This identification information includes, for example, the typeof slice dividing or tile dividing (slice_type, tile_type), the indexinformation for specifying slices or tiles (slice_idx, tile_idx), thegeometry information of data (slices or tiles), or the address of data,etc. The index information for specifying slices is also written as theslice index (SliceIndex). The index information for specifying tiles isalso written as the tile index (TileIndex). Additionally, the type ofdivision is, for example, the technique based on an object shape asdescribed above, the technique based on map information or geometryinformation, or the technique based on the data amount or processingamount, etc.

Note that all or a part of the above-described information may be storedin one of the header of divided geometry information and the header ofdivided attribute information, and may not be stored in the other. Forexample, when the same dividing method is used for geometry informationand attribute information, the type of division (slice_type, tile_type)and the index information (slice_idx, tile_idx) for the geometryinformation and the attribute information are the same. Therefore, theseinformation may be included in the header of one of the geometryinformation and the attribute information. For example, when attributeinformation depends on geometry information, the geometry information isprocessed first. Therefore, these information may be included in theheader of the geometry information, and these information may not beincluded in the header of the attribute information. In this case, thethree-dimensional data decoding device determines that, for example, theattribute information of a dependence source belongs to the same sliceor tile as a slice or tile of the geometry information of a dependencedestination.

Furthermore, additional information (slice additional information,geometry tile additional information, or attribute tile additionalinformation) related to slice dividing or tile dividing, and dependencyinformation indicating dependency, etc. may be stored and transmitted inan existing parameter set (GPS, APS, geometry SPS, or attribute SPS).When the dividing method is changed for each frame, the informationindicating the dividing method may be stored in the parameter set (GPSor APS) for each frame. When the dividing method is not changed within asequence, the information indicating the dividing method may be storedin the parameter set (geometry SPS or attribute SPS) for each sequence.Furthermore, when the same dividing method is used for geometryinformation and attribute information, the information indicating thedividing method may be stored in the parameter set of a PCC stream(stream PS).

Also, the above-described information may be stored in any of theabove-described parameter sets, or may be stored in a plurality of theparameter sets. Additionally, a parameter set for tile dividing or slicedividing may be defined, and the above-described information may bestored in the parameter set. Furthermore, these information may bestored in the header of encoded data.

Also, the header of encoded data includes the identification informationindicating dependency. That is, when there is dependency between data,the header includes the identification information for referring to adependence destination from a dependence source. For example, the headerof data of a dependence destination includes the identificationinformation for specifying the data. The identification informationindicating the dependence destination is included in the header of thedata of a dependence source. Note that, when the identificationinformation for specifying data, the additional information related toslice dividing or tile dividing, and the identification informationindicating dependency can be identified or derived from otherinformation, these information may be omitted.

Next, the flows of encoding processing and decoding processing of pointcloud data according to the present embodiment will be described. FIG.57 is a flowchart of the encoding processing of point cloud dataaccording to the present embodiment.

First, the three-dimensional data encoding device determines thedividing method to be used (S4911). This dividing method includeswhether or not to perform slice dividing, and whether or not to performtile dividing. Also, the dividing method may include the number ofdivisions and the type of division, etc. in the case of performing slicedividing or tile dividing. The type of division is the technique basedon an object shape as described above, the technique based on mapinformation or geometry information, or the technique based on the dataamount or processing amount, etc. Note that the dividing method may bedefined in advance.

When slice dividing is performed (Yes in S4912), the three-dimensionaldata encoding device generates a plurality of slice geometry informationand a plurality of slice attribute information by collectively dividinggeometry information and attribute information (S4913). Also, thethree-dimensional data encoding device generates slice additionalinformation related to slice dividing. Note that the three-dimensionaldata encoding device may separately divide geometry information andattribute information.

When tile dividing is performed (Yes in S4914), the three-dimensionaldata encoding device generates a plurality of divided geometryinformation and a plurality of divided attribute information byseparately dividing the plurality of slice geometry information and theplurality of slice attribute information (or geometry information andattribute information) (S4915). Additionally, the three-dimensional dataencoding device generates geometry tile additional information andattribute tile additional information related to tile dividing. Notethat the three-dimensional data encoding device may collectively divideslice geometry information and slice attribute information.

Next, the three-dimensional data encoding device generates a pluralityof encoded geometry information and a plurality of encoded attributeinformation by encoding each of the plurality of divided geometryinformation and the plurality of divided attribute information (S4916).Also, the three-dimensional data encoding device generates dependencyinformation.

Next, the three-dimensional data encoding device generates encoded data(an encoded stream) by forming (multiplexing) the plurality of encodedgeometry information, the plurality of encoded attribute information,and additional information into a NAL unit (S4917). Also, thethree-dimensional data encoding device transmits the generated encodeddata.

FIG. 58 is a flowchart of the decoding processing of point cloud dataaccording to the present embodiment. First, the three-dimensional datadecoding device determines the dividing method by analyzing additionalinformation (slice additional information, geometry tile additionalinformation, and attribute tile additional information) related to thedividing method included in the encoded data (encoded stream) (S4921).This dividing method includes whether or not to perform slice dividing,and whether or not to perform tile dividing. Additionally, the dividingmethod may include the number of divisions and the type of division,etc. in the case of performing slice dividing or tile dividing.

Next, the three-dimensional data decoding device generates dividedgeometry information and divided attribute information by decoding aplurality of encoded geometry information and a plurality of encodedattribute information included in the encoded data by using dependencyinformation included in the encoded data (S4922).

When it is indicated by the additional information that tile dividinghas been performed (Yes in S4923), the three-dimensional data decodingdevice generates a plurality of slice geometry information and aplurality of slice attribute information by combining a plurality ofdivided geometry information and a plurality of divided attributeinformation with respective methods based on geometry tile additionalinformation and attribute tile additional information (S4924). Note thatthe three-dimensional data decoding device may combine the plurality ofdivided geometry information and the plurality of divided attributeinformation with the same method.

When it is indicated by the additional information that slice dividinghas been performed (Yes in S4925), the three-dimensional data decodingdevice generates geometry information and attribute information bycombining the plurality of slice geometry information and the pluralityof slice attribute information (the plurality of divided geometryinformation and the plurality of divided attribute information) with thesame method based on slice additional information (S4926). Note that thethree-dimensional data decoding device may combine the plurality ofslice geometry information and the plurality of slice attributeinformation with respective different methods.

As described above, the three-dimensional data encoding device accordingto the present embodiment performs the processing illustrated in FIG. 59. First, the three-dimensional data encoding device performs dividinginto a plurality of divided data (for example, tiles) included in aplurality of subspaces (for example, slices) divided from a currentspace in which a plurality of three-dimensional points are included,each of the plurality of divided data including one or morethree-dimensional points. Here, the divided data is one or more dataaggregates that are included in a subspace, and includes one or morethree-dimensional points. Additionally, the divided data is also spaces,and may include a space that does not include a three-dimensional point.Furthermore, a plurality of divided data may be included in onesubspace, or one divided data may be included in one subspace. Note thata plurality of subspaces may be set to a current space, or one subspacemay be set to the current space.

Next, the three-dimensional data encoding device generates a pluralityof encoded data corresponding to a plurality of divided data,respectively, by encoding each of the plurality of divided data (S4931).The three-dimensional data encoding device generates a bit streamincluding the plurality of encoded data and a plurality of controlinformation (for example, the headers illustrated in FIG. 56 ) (referredto also as signaling information) for the plurality of respectiveencoded data (S4932). In each of the plurality of control information, afirst identifier (for example, slice_idx) indicating the subspacecorresponding to the encoding data corresponding to the controlinformation, and a second identifier (for example, tile_idx) indicatingthe divided data corresponding to the encoding data corresponding to thecontrol information are stored.

According to this, the three-dimensional data decoding device thatdecodes a bit stream generated by the three-dimensional data encodingdevice can easily restore a current space by combining the data of aplurality of divided data by using the first identifier and the secondidentifier. Therefore, the processing amount in the three-dimensionaldata decoding device can be reduced.

For example, in the encoding, the three-dimensional data encoding deviceencodes the geometry information and attribute information of athree-dimensional point(s) included in each of the plurality of divideddata. Each of a plurality of encoded data includes the encoded data ofgeometry information, and the encoded data of attribute information.Each of a plurality of control information includes the controlinformation of the encoded data of geometry information, and the controlinformation of the encoded data of attribute information. The firstidentifier and the second identifier are stored in the controlinformation of the encoded data of geometry information.

For example, in a bit stream, each of a plurality of control informationis located ahead of the encoded data corresponding to the controlinformation.

Additionally, a current space in which a plurality of three-dimensionalpoints are included is set as one or more subspaces, one or more divideddata including one or more three-dimensional points are included in thesubspaces, the three-dimensional data encoding device generates aplurality of encoded data corresponding to the plurality of respectivedivided data by encoding each of the divided data, and generates a bitstream including the plurality of encoded data and a plurality ofcontrol information for the plurality of respective encoded data, andthe first identifier indicating the subspace corresponding to theencoded data corresponding to the control information, and the secondidentifier indicating the divided data corresponding to the encoded datacorresponding to the control information may be stored in each of theplurality of control information.

For example, the three-dimensional data encoding device includes aprocessor and a memory, and the processor performs the above-describedprocessing by using the memory.

Additionally, the three-dimensional data decoding device according tothe present embodiment performs the processing illustrated in FIG. 60 .First, the three-dimensional data decoding device obtains the firstidentifier (for example, slice_idx) and the second identifier (forexample, tile_idx) from a bitstream, the bitstream including a pluralityof encoded data and a plurality of control information (for example, theheaders illustrated in FIG. 56 ) corresponding to the plurality ofrespective encoded data, the first identifier and the second identifierbeing included in the plurality of control information, the plurality ofencoded data being generated by encoding each of a plurality of divideddata (for example, tiles), the plurality of divided data being includedin a plurality of subspaces (for example, slices) obtained by dividing acurrent space including a plurality of three-dimensional points, theplurality of divided data each including one or more three-dimensionalpoints, the first identifier indicating a subspace corresponding to theencoded data corresponding to the control information, the secondidentifier indicating the divided data corresponding to the encoded datacorresponding to the control information (S4941). Next, thethree-dimensional data decoding device restores a plurality of divideddata by decoding the plurality of encoded data (S4942). Next, thethree-dimensional data decoding device restores the current space bycombining the plurality of divided data by using the first identifierand the second identifier (S4943). For example, the three-dimensionaldata decoding device restores the plurality of subspaces by combiningthe plurality of divided data by using the second identifier, andrestores the current space (the plurality of three-dimensional points)by combining the plurality of subspaces by using the first identifier.Note that the three-dimensional data decoding device may obtain theencoded data of a desired subspace or divided data from a bit stream byusing at least one of the first identifier and the second identifier,and may selectively decode or preferentially decode the obtained encodeddata.

According to this, the three-dimensional data decoding device can easilyrestore the current space by combining the data of the plurality ofdivided data by using the first identifier and the second identifier.Therefore, the processing amount in the three-dimensional data decodingdevice can be reduced.

For example, each of the plurality of encoded data is generated byencoding the geometry information and attribute information of thethree-dimensional point(s) included in the corresponding divided data,and includes the encoded data of the geometry information, and theencoded data of the attribute information. Each of the plurality ofcontrol information includes the control information of the encoded dataof the geometry information, and the control information of the encodeddata of the attribute information. The first identifier and the secondidentifier are stored in the control information of the encoded data ofthe geometry information.

For example, in a bit stream, the control information is located aheadof the corresponding encoded data.

For example, the three-dimensional data decoding device includes aprocessor and a memory, and the processor performs the processesdescribed above using the memory.

A three-dimensional data encoding device, a three-dimensional datadecoding device, and the like according to the embodiments of thepresent disclosure have been described above, but the present disclosureis not limited to these embodiments.

Note that each of the processors included in the three-dimensional dataencoding device, the three-dimensional data decoding device, and thelike according to the above embodiments is typically implemented as alarge-scale integrated (LSI) circuit, which is an integrated circuit(IC). These may take the form of individual chips, or may be partiallyor entirely packaged into a single chip.

Such IC is not limited to an LSI, and thus may be implemented as adedicated circuit or a general-purpose processor. Alternatively, a fieldprogrammable gate array (FPGA) that allows for programming after themanufacture of an LSI, or a reconfigurable processor that allows forreconfiguration of the connection and the setting of circuit cellsinside an LSI may be employed.

Moreover, in the above embodiments, the structural components may beimplemented as dedicated hardware or may be realized by executing asoftware program suited to such structural components. Alternatively,the structural components may be implemented by a program executor suchas a CPU or a processor reading out and executing the software programrecorded in a recording medium such as a hard disk or a semiconductormemory.

The present disclosure may also be implemented as a three-dimensionaldata encoding method, a three-dimensional data decoding method, or thelike executed by the three-dimensional data encoding device, thethree-dimensional data decoding device, and the like.

Also, the divisions of the functional blocks shown in the block diagramsare mere examples, and thus a plurality of functional blocks may beimplemented as a single functional block, or a single functional blockmay be divided into a plurality of functional blocks, or one or morefunctions may be moved to another functional block. Also, the functionsof a plurality of functional blocks having similar functions may beprocessed by single hardware or software in a parallelized ortime-divided manner.

Also, the processing order of executing the steps shown in theflowcharts is a mere illustration for specifically describing thepresent disclosure, and thus may be an order other than the shown order.Also, one or more of the steps may be executed simultaneously (inparallel) with another step.

A three-dimensional data encoding device, a three-dimensional datadecoding device, and the like according to one or more aspects have beendescribed above based on the embodiments, but the present disclosure isnot limited to these embodiments. The one or more aspects may thusinclude forms achieved by making various modifications to the aboveembodiments that can be conceived by those skilled in the art, as wellforms achieved by combining structural components in differentembodiments, without materially departing from the spirit of the presentdisclosure.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to a three-dimensional dataencoding device and a three-dimensional data decoding device.

What is claimed is:
 1. A three-dimensional data encoding method,comprising: encoding a plurality of divided data items to generate aplurality of encoded data items each corresponding to a respective oneof the plurality of divided data items, the plurality of divided dataitems being included in a plurality of subspaces obtained by dividing acurrent space, the plurality of divided data items each including athree-dimensional point from among a plurality of three-dimensionalpoints included in the current space; and generating a bitstream,wherein the encoding includes, for each of the plurality of divided dataitems, (i) encoding geometry information corresponding thethree-dimensional point included in the divided data item to generateencoded geometry information for an encoded data item corresponding tothe divided data item, and (ii) encoding attribute informationcorresponding to the geometry information to generate encoded attributeinformation for the encoded data item corresponding to the divided dataitem, and wherein the bitstream includes, for each of the encoded dataitems, a combination of the encoded geometry information for the encodeddata item and control information for encoded data item, the controlinformation including (a) a first identifier indicating a subspacecorresponding to the encoded data item from among the plurality ofsubspaces, and (b) a second identifier indicating a divided data itemcorresponding to the encoded data item from among the plurality ofdivided data items.
 2. A three-dimensional data decoding method,comprising: obtaining a plurality of encoded data items from abitstream, the bitstream including a plurality of encoded data itemsgenerated by encoding a plurality of divided data items, each of theplurality of encoding data items corresponding to a respective one ofthe plurality of divided data items, the plurality of divided data itemsbeing included in a plurality of subspaces obtained by dividing acurrent space, the plurality of divided data items each including athree-dimensional point from among a plurality of three-dimensionalpoints included in the current space, wherein the encoding includes, foreach of the plurality of divided data items, (i) encoding geometryinformation corresponding the three-dimensional point included in thedivided data item to generate encoded geometry information for anencoded data item corresponding to the divided data item, and (ii)encoding attribute information corresponding to the geometry informationto generate encoded attribute information for the encoded data itemcorresponding to the divided data item, wherein the bitstream includes,for each of the encoded data items, a combination of the encodedgeometry information for the encoded data item and control informationfor encoded data item, the control information including (a) a firstidentifier indicating a subspace corresponding to the encoded data itemfrom among the plurality of subspaces, and (b) a second identifierindicating a divided data item corresponding to the encoded data itemfrom among the plurality of divided data items, and wherein thethree-dimensional data decoding method further comprises: decoding theplurality of encoded data items to obtain the plurality of divided dataitems; obtaining the first identifiers and the second identifiers fromthe bitstream; and combining the plurality of divided data itemstogether with reference to the second identifiers to reconstruct thecurrent space.
 3. A three-dimensional data encoding device, comprising:a processor; and memory, wherein, using the memory, the processor:encodes a plurality of divided data items to generate a plurality ofencoded data items each corresponding to a respective one of theplurality of divided data items, the plurality of divided data itemsbeing included in a plurality of subspaces obtained by dividing acurrent space, the plurality of divided data items each including athree-dimensional point from among a plurality of three-dimensionalpoints included in the current space; and generates a bitstream,wherein, for each of the plurality of divided data items, the processor(i) encodes geometry information corresponding the three-dimensionalpoint included in the divided data item to generate encoded geometryinformation for an encoded data item corresponding to the divided dataitem, and (ii) encodes attribute information corresponding to thegeometry information to generate encoded attribute information for theencoded data item corresponding to the divided data item, and whereinthe bitstream includes, for each of the encoded data items, acombination of the encoded geometry information for the encoded dataitem and control information for encoded data item, the controlinformation including (a) a first identifier indicating a subspacecorresponding to the encoded data item from among the plurality ofsubspaces, and (b) a second identifier indicating a divided data itemcorresponding to the encoded data item from among the plurality ofdivided data items.
 4. A three-dimensional data decoding device,comprising: a processor; and memory, wherein, using the memory, theprocessor: obtains a plurality of encoded data items from a bitstream,the bitstream including a plurality of encoded data items generated byencoding a plurality of divided data items, each of the plurality ofencoding data items corresponding to a respective one of the pluralityof divided data items, the plurality of divided data items beingincluded in a plurality of subspaces obtained by dividing a currentspace, the plurality of divided data items each including athree-dimensional point from among a plurality of three-dimensionalpoints included in the current space, wherein the encoding includes, foreach of the plurality of divided data items, (i) encoding geometryinformation corresponding the three-dimensional point included in thedivided data item to generate encoded geometry information for anencoded data item corresponding to the divided data item, and (ii)encoding attribute information corresponding to the geometry informationto generate encoded attribute information for the encoded data itemcorresponding to the divided data item, wherein the bitstream includes,for each of the encoded data items, a combination of the encodedgeometry information for the encoded data item and control informationfor encoded data item, the control information including (a) a firstidentifier indicating a subspace corresponding to the encoded data itemfrom among the plurality of subspaces, and (b) a second identifierindicating a divided data item corresponding to the encoded data itemfrom among the plurality of divided data items, and wherein theprocessor further: decodes the plurality of encoded data items to obtainthe plurality of divided data items; obtains the first identifiers andthe second identifiers from the bitstream; and combines the plurality ofdivided data items together with reference to the second identifiers toreconstruct the current space.